432 



NATURE 



\Sept. 26, 1872 



On the Substance Exhibited at the British Association, 

 Brighton, by Mr. P. L. Sclater, and stated to be the 

 OoSiflad Notochord of a Fish 



Nk.vrly every one frequenting the Zoological Section at the 

 British Association at Brighton must have seen and been puzzled 

 by a substance exactly resembUnj in external appearance a slen- 

 der willow twig when perfect, two feet or more in length, and 

 pointed at both ends. 



This substance was exhibited by Mr. Sclater, and pieces of it 

 were freely distributed by him fur examination. 



I was, unfortunately, not present when he read his paper on 

 the subject ; but I gathered that he had said that the substance 

 had been described to him by the person who sent it as occur- 

 ring in tlie back of a fish, and tliat Mr. .Sclater called it an ossi- 

 fi ;d n itochord. A drawing of the fish was exhibited. 

 • I farther heard that Mr. Gray, of the British Museum, re- 

 garded the substance as the axis of one of the Pennatulidie, and 

 thit this opinion was held by several other niturallsts also. 



I first became acquainted witli the substance at the Kew Iler- 

 birlutn, where a piece of it w.i,s shown me iiy Mr. Berl<eley, it 

 having been given to him by Prof. Thiselton Dyer ; and I was 

 told tiat Dr. Hooker had examined it with the microscope, and 

 rejected it as certainly not vegetable. 



It was almost impossible to conceive of the substance being the 

 notochord of a fish. No fish's notochord is composed of longi- 

 tudinal fibres, nor lias a structure at all resembling that of the 

 substance in question ; and moreover a notochord in such a fish 

 as a lamprey, in which it is periistent, is much thicker in propor- 

 tion to its length than are these calcified rods. Further, the 

 tendency is for a notochord to ossify peripherally, and form rings 

 of bone, not a hardened central core. 



On reaching Oxf jrd from Brighton, I got Mr. Robertson to 

 give me a specimen of Fiinitul.via quadrangnlaris, one of the 

 Pennatulidx, whicli was jireserved in spirits. I found it had a 

 long slender flexible core, exactly similar in appeanince to Mr. 

 Sclater's substance, bat quadrangular in section instead of circular. 

 The core was about two feet and a half long, and pointed at 

 both ends. Microscopical examin.ation of longitudinal sections 

 of the core, when treated with acetic acid, gave off carbonic acid 

 in quantities, and showed a structure almost exactly resembling 

 that observed under similar circumstances in Mr. Sclater's sub- 

 stance. 



I then looked into the literature of the subject, which fully 

 confirmed me in the opinion that the substance in question is the 

 core of one of the Pennatulidii,'. A few statements, culled from 

 the two works I consulted, maybe interesting to the readers 

 of N.\rtiRE. The works were " Anitoraisch-systemitische 

 Beschreibung der Alcyonarien," von A. KoUiker, Erste Ab- 

 t'leilung : Die Pennatuliden. Erste Halfte (Frankfort: C. Win- 

 ter, 1S70). " Icones Histologics, oderAtUs der Vergleichenden 

 Gewebelehre," herausgegcben von A. KoUiker. Zweite Ab- 

 theilung, Erster Heft. Die Binde-substanz der Ccelenteraten, 

 p. 158 (Leipzig: W. Engelman, lS66). 



The Alcyonariae, a sub-order of polyps, are divided into three 

 groiips : — (I) Alcyonidrc ; (2) Gorgonidce ; (3) Pennatulidce. 



The Pennatulidae consist of hard and soft parts. The hard 

 parts appear in most varieties in the form of an inner calcified 

 axis, which in size and position is like that of the Gorgonidie. 

 It is to be considered as calcified connective tissue, is entirely 

 and ompletely enclosed within the substance of the polyp 

 colony, and is pointed at both ends. 



The Pennatulida; are thus divided : — 



I. Pennatulida; with polypbearers bilaterally symmetrical. 



A. Polypbearers feather-shaped in Pennatulea;. 



B. Polypbearers leaf-shaped in Renillacere. 



II. Pennatulida-, with polyps arranged radially. 



The Pennatulea: break up into (i) Penniformes ; Pennatule;^; 

 with a well-marked feather-shape ; (2) Virgulariex ; Pennatule.v.' 

 with a long, narrow polypbearer, and small leaves or polyps rest- 

 ing immediately on the axis. To this latter group belongs the 

 genus Fnnkularia, and probably also the genus to which Mr. 

 Sclater's specimen belongs. 



With regard to the fine structure of the hard axis of Penna- 

 tulida;, I have gathered the following from Kblliker's "Icones," 

 p. 158. 



Tlie axes of Pennatulidx' consist of calcified horny substance, 

 arranged in concentric lamelUi; about a central core. The 

 lamella' aie pierced by peculiar soft radial fibres, which, how- 

 ever, are well defined in certain species only. The organic 

 basal substance shows an extremely well marked fibrillar structure. 



The axes are less firmly calcified than those of the Gorgonidie, 

 and are thus for the most part able to be cut with a knife and 

 bent. 



According to the analys?s of Fremy (Ann. de Chimie, 1S55, 

 t. xliii. p. gS), the axnoi Pleroi'iJa sfiinosum contiins from 31 to 

 40 per cent, mineral matter, and that of Pcuu.itula rubra from 

 45 to 48 per cent. 



A drawing is given by KoUiker of a transverse seclion of t' e 

 axis of a Virgularia {Lygiis mirabilis) prepared by grindin.', whicU 

 shows a white central core, surrounded by a broid bro vnisli 

 cortex, which is marked with concentric and radial lines. 



If the axis of a Lviiis be treated with acetic acid, a dov lo - 

 ment of carbonic acid takes place. It becomes soft, and allows 

 the following structure to be made out : — 



The bulk of the axis consists of a fibrous tissue which re- 

 sembles ordinary fibrillar connective tissue in the most deceptive 

 manner, and consists of very fine fibrillre, which run parallel to 

 one another in a wavy fashion, and which can be isolated from 

 one another. On the surface of the axis is a yellowish cuticle. 



Drawings are given of longitudinal sections of the axis of 

 Lygns inlrabilis. It shows the peculiar broad transparent radial 

 fibres crossing the finer longitudinal ones. In another figure of 

 a similar preparation from FnnicuJaria quadraiigularis, these 

 r.adiil fibres are less marked, but the cavities containing them 

 appear as oval apertures in the section. 



Reference is male to Ousl'stt, Lectures on Histology, IL, and 

 Histological Catalogue, I., where the structure of the axes of 

 PicrojiJes, Lygiis, and Fnnkularia is described, but the radial 

 fibres mistaken for canals. 



I think any one who has examined Mr. Sclater's substance, 

 and very many have had such an opportunity owing to his kind- 

 ness in distributing pieces, will find that both in external charac- 

 teristics and internal microscopical structure, it conforms very 

 closely to the description given here from KoUiker of the axis of 

 the Pennatulid. I have sent the Editor of Nature some pieces of 

 the axis of /■'uiiiiii/dn'a (juadrnii^iilaris in case any one cares to 

 compare the two substances, and has not the material at hand. 

 In the mean time I cannot but conclude that Mr. Sclater has 

 been misinformed, and that we are very unlikely ever to see that 

 very marvellous fish in the flesh. 



H. N. MOSELEY 



Ocean Currents 



Having just returned from a sojourn of nearly two mon hs 

 amongst the White Mountains, I am now for the first made aware 

 of the publication, both of my last note on Ocean Currents, and 

 also of Mr. CroU's reply. I have not been disposed to enter into 

 an extended discussion of this subject, knowing that it cannot be 

 properly treatel without the use of mathematics, in short essays 

 suited to Nature, and doubting whether the discussion could 

 be ra.ade either acceptable to its Editor or edifying to is readers. 

 In my last note, therefore, I endeavoured to be as brief as 

 possible, and considered only the more simple form of the con- 

 ditions of the problem, as expressed by differential equa'ions, 

 showing the relations between the forces, resistances, and the 

 differentials of the motions, and showed that the deflecting force 

 eastward exerted upon a pound of water or any body in movi^ig 

 toward the pole with a velocity of one mile per day, and which 

 must be sensibly the measure of the resistance of friction, is of 

 the same order near the parallel of 45° as the action of gravity 

 on the same body upon a gradient of 6 ft. from the equator to 

 the pole ; and from tidal considerations it was inferred that the 

 resistances to the slow motions of ocean currents may be very 

 much less than the action of gravity upon any body apon a gra- 

 dient of 6 ft. in the distance of a quadrant. 



If, instead of considering the differential equations of any 

 problem, and endeavouring to satisfy them directly, we adopt ihe 

 less simple method, .and consider the integrals of these equations, 

 and endeavour to satisfy them directly, the method, though le.-s 

 simple, is entirely legitimate, and we should obtain the same re- 

 sults. This is substantially the method adopted by Mr. Croll ; 

 and from considering the problem in this way, he comes to the 

 conclusion that the deflecting force eastvvard, which is the 

 measure of the resistance, is at least 1,500 times greater than the 

 action of gravity on a gradient of 6 ft. from the equator to the 

 parallel of 60" ; and as the velocity of the pound of water east- 

 ward, and that toward the pole, are probably about of the same 

 order, and consequently the resistances, he justly infers that the 

 resistance to the motion toward the pole must be overcome by 



