in which Mr. Dana mentions an agreement, a reader would infer that I had totally overlooked them. In Dendrophyllia ramea, a certain but limited connexion apparently exists, for a time at least, between the animal matter which occupies the interior of a stem or branch, and that which invests it. The great thickening of the coral, however, is effected by means of the mantle which covers the exterior and forms more or less concentric layers. This mantle often extends also over portions of an adjacent branch, which had, apparently, been deprived of vitality, and deposits additional layers on that branch. In such cases, there could be no connexion between the mantle and interior of the encrusted branch. This process Mr. Dana expressly alludes to in p. 385 of his work. No concentric depositions are visible in the sections of specimens No. 2, and it was with reference to the successive layers formed on the surface of Dendrophyllia by the external mantle; and the evidence in the Alabama coral of a totally different operation, that the term Endopachys was adopted, certain structural agreements having been shown to exist between the two genera.

I hope this explanation if clear will vindicate me from having inconsiderately named your coral.

Madrepora tubulata, Mr. Dana says, "is an Oculina," p. 221. Your specimens had only twelve lamellæ.* Oculinæ have more than twelve. Madreporæ have only twelve. This structural distinction is very generally accepted. Internally the American coral agreed far more closely with Madrepora than Oculina, so far as its state of preservation warranted an opinion. The chief objection to the generic assignment is in the mode of developing additional abdominal cavities, and this was felt at the time; but not mentioned because I was not certain that that process was universal throughout the genus. Mr. Dana in his work, p. 486, received long after the notice was printed, describes three species of Madrepora, in which the normal process is apparently deviated from. On this, however, I would not for a moment rest as a justification. I named the coral after a careful examination of the imperfect evidence before me, and placed it in the newest, allied, established genus, the specimens not justifying the proposing a new genus. The reply to the critic might be: It is not an Oculina.

Columnaria? sexradiata.-The note of interrogation should not have been omitted by Mr. Dana. It is stated that the fossil is allied to Astræa calicularis, and Mr. Dana in his description of the latter, refers to Esper, pl. 16, Fig. 12. The coral there represented, is generically if not specifically allied to the fine zoophyte you kindly gave me, and is labelled "Caryophyllia-from Lieut. Holland, Prince's Island, west coast of Africa."

*See notice, Geological Journal, vol. i, p. 520. t Silliman's Journal, p. 221.

Astræa calicularis, (auct.) is found in the Mediterranean. If I am right in identifying Esper's figure with the African specimen, generically, and I have no doubt there is no agreement whatever between Astræa or Astroitis calicularis and the American fossil, every essential character being different, except that the additional stellated cavities are in the Columnaria? sexradiata interstitial, but even in this respect, there are many important differences— Mr. Dana should have thought a little more, or given fuller grounds for dissent.

Astræa hirto-lamellata? (it must be for the future, Astræa Marylandica, Conrad.) This fossil is said to be closely allied to the preceding. (Query, Col? sexradiata? or Astroitis calicularis?) In the notice of the fossil* allusion is made to a subdivided star, and though the statement is cautiously put, I had little doubt at the time of the inference being correct. That process is one of the leading characters of Astraa as rightly restricted by Ehrenberg, and it is totally wanting in Columnaria? or Astroitis. Of Mr. Dana's Pleiadia no full account has, I believe, been published.

I have troubled you with a long letter of personal justification, but it is due to yourself to shew, that I did not abuse the trust you kindly committed to my care.

ART. XXXI.-Observations in reply to Mr. Lonsdale's "Remarks;" by JAMES D. DANA.

THE Ordinary coral Zoophytes have been so imperfectly studied in a zoological point of view, that no discredit whatever can properly attach to errors of judgment in the cultivators of this department of science. This is especially true with regard to Mr. Lonsdale, whose labors evince throughout, careful and assiduous study of the best authorities in this branch of science, and a success well worthy the honor conferred on him by the Geological Society of London.

The suggestions in the volume of this Journal referred to by him, made by me after protracted researches among living species of zoophytes, were thrown out to promote the interests of science, and if erroneous, will be as readily retracted, and for the same purpose. But several facts are believed to sustain my former conclusions which I will endeavor to explain.

Genus Endopachys.-The pores or foramina described as characterizing this genus, I have observed in the Dendrophyllia nigrescens,† (D.) from the Feejees, and also still more perfectly in the D. scabrosa,‡ (D.) closely resembling specimens I have seen

*Geological Journal, vol. i, p. 500. + Report on Zoophytes, p. 387.

+ Ib. p. 390.

of the Endopachys. This character according to my observations, is one of the least important among corals. In Astræa, Pocillopora as well as Dendrophyllia, (and also other genera,) there is every variety in this character, from the most solid, to the most cellular texture. The same species at times is full of pores in the early state and becomes quite solid in a more advanced condition. From the manner in which the coral is secreted, it is also obvious that the character cannot be important. The secretions take place among the tissues, beneath the skin. They are sometimes so general as to form a solid texture without visible pores, and in other cases, where certain of the animal fibres do not add to the secretions, there are pores larger or smaller, occupied by these animal tissues. These tissues form a communication between the interior and exterior; they occur in the most compact coral, though not visible except in thinly polished fragments examined with a lens, or after digestion in an acid which removes the calcareous material. After the coral is begun in the young animal, it is constantly receiving addition to its surface. A common mode, illustrated in the species of the genera Madrepora, Dendrophyllia and others, consists first in the secretion taking place in points, so as to raise minute prominences on the surface; and next, after the points are more or less elongated, the secretion becomes more general, and all the points are connected by the calcareous secretions, which thus make a net-work or layer, over the whole. In a transverse section of most Madrepores, the successive series of minute columns are well shown. In the Dendrophyllias referred to, and even in some specimens of the D. ramea, the same structure is apparent. When the points are obsolete, the coral will consist of layers of lime, as is sometimes apparent. Often again there is no regularity or approach to layers in the porous structure, as in D. scabrosa, &c.

As the animals grow, the pores which contain living fibres in the young state, often gradually diminish by the secretions from the surface of these fibres, which themselves are gradually disappearing, and the coral which was before very porous may finally become solid. Almost every genus illustrates this point. The exterior fleshy part of the animal is in no sense "a mantle," (any more than the skin of an Actinia,) and it is not known ever to extend itself over a part once dead.

If Mr. Lonsdale means simply by "thickening from within,” that nourishment and calcareous material are distributed outward from the visceral cavity, (which I suppose is not precisely his view,) then his character will apply to nearly all coral zoophytes; for all cellular coral species have free circulation of the chyloid fluids wherever there are tissues, and these fluids are derived from the stomach and visceral cavity; and the invisible fibres of the more solid species may also have this function; whether so or not, the character is of little importance.

There seems therefore to be reason for dissenting from Mr. Lonsdale, as to the importance of the characteristic upon which he has established his genus.

Madrepora tubulata.-The genus Madrepora, characterized by an apical polyp to each branch, graduates into Manopora (D.), when the distinction of apical polyp is lost. The latter are foliaceous and glomerate species having the cell of the Madreporæ in every particular, but with irregular calicles or none; they include the species of the genus Montipora of Blainville, based on the existence of warty prominences over the corallum between the cells, (a character without importance and of impracticable application;) and also a part of the Porites of Lamark, (Porites spumosa, &c.) And as the transition is very gradual there are intermediate species, two or three of which I have referred to Madrepora, since they have regular calicles although the apical polyp cannot be distinguished.* But the structure of Oculina is in no respect represented or approximated to. Indeed the mode of budding of this genus, allies it more nearly to the Astræa family, in which certain branching species show the alternate gemmation at apex characterizing Oculina. Hence the species referred to is far removed from Madrepora; and if it be not an Oculina (by having but twelve lamellæ, and twelve tentacles to the polyps) it must either belong to a new genus, or else the characters of Oculina should be so extended as to include it. I have been long convinced that the number 12, has been allowed too much authority, and have so far infringed upon it in my treatise on Zoophytes as to unite the genera Porites and Goniopora into a single family.

But from Mr. Lonsdale's figure, it is evident that the animal had normally more than 12 tentacles, and that the lamellæ are but 12 in number because part are obsolete. The striæ around the cell are a more correct indication of the character of the animal, than the lamellæ alone.

Columnaria? sexradiata, (L.) Astræa hirto-lamellata, (Mich.) -These species are still more ambiguous cases, about which there may be an honorable difference of opinion. Having examined the corals referred to, I came to the conclusion, which I still hold, that in one essential character, the species are rather allied to the Caryophyllia family, than the Astræa; notwithstand

It is interesting to trace the transitions between these genera. In Madrepora, the horizontally growing species, form a series, in which the branches are more and more coalescent, till at last they form a solid plate, (M. palmata,) whose edges only here and there show the tips of the branches of which it is composed. The next step beyond this, is an absence wholly of the branchlets, and the species is a simple leaf or folium growing at margin. In all known species, when this step is reached, the calicles are very imperfect or wanting, and they are Manopore. In the same manner other Madreporæ pass into species with stout branches, in which the terminal polyp is hardly distinguishable (M cuneata and the allied); and the next step is a glomerate Manopora. Thus there are two lines of gradation from Madrepora into Manopora.

SECOND SERIES, Vol. IV, No. 12.-Nov., 1847.

46

ing the structure of the coral. As in conchology, the calcareous secretions sometimes may entirely mislead.

The Astrea calicularis, and other species figured by Quoy and Gaymard, in the Voyage of the Astrolabe, are closely like Astræas in their corals. Yet the polyps are very prominent above the coral when expanded, each very much projecting, and attached to the adjoining only at base. They are like the Goniopora in this respect. An Astræa increases by a lateral summit growth. and budding, the summit gradually extending, and at the same time forming young polyps as buds. When the polyps are connected only at base, as in the A. calicularis, the budding is lateral from near the base and not terminal, and the species are therefore excluded by this characteristic from the Astræa family, and most strikingly from the genus Astræa. From an examination of a recent coral on the coast, very near the Astræa Marylandica of Conrad, I have been led to refer the whole to a group characterized by exsert polyps. The correctness of this reference cannot be fully established until the animals of the recent species are known; and I have waited for an opportunity to make the examination before describing it.

In this species, and also in specimens of A. Marylandica, examined by the writer, the polyps do not appear to bud by subdivisions.

The relation of the species designated by Mr. Lonsdale Columnaria (?) sexradiata, to the genus Columnaria, is only in mode of growth and not in structure.

ART. XXXII.-Notice of a Water-Spout; by ELIAS LOOMIS.

On Friday morning, Aug. 20th, 1847, it was my good fortune to witness a water-spout in unusual perfection. I left Erie, Penn., in a steamboat for Cleveland, Ohio, about seven o'clock, with a pretty fresh breeze from the west southwest. The sky was for the most part clear; but there were numerous floating clouds, and in particular one dark mass of clouds arose in the west affording some indications of a shower. These clouds passed nearly over our boat, but brought us no rain. As they moved off to the east, about half past eight, an imperfect water-spout was seen, in the form of a funnel-shaped cloud, suspended from the base of the black mass already mentioned. It bore some resemblance to an elephant's trunk, and curved downward towards the south. It appeared dangling in the air, and terminated at a distance from the water about equal to the length of the trunk. No particular agitation of the water was noticed beneath it. In a few minutes it had disappeared; but presently a second spout was noticed which