68 



teorological observations for 1354, made at Penii 

 Yan, N. Y. 



Dr. Ayres presented the following communica- 

 tion : 



TkeEchiuodermata of the coast of California have 

 hitherto received but a small share of study, and 

 in asking the attention of the Academy this evening, 

 to some remarks concerning them, we are soliciting 

 notice to a field almost entirely untrodden. 



In numbers both of species and individuals, they 

 appear scarcely to equal those of the corresponding 

 latitudes of the Atlantic. It is but just to observe 

 that my own researches have already been sufficient 

 to furnish data that warrant this conclusion, though 

 undoubtedly many species yet remain to be detected. 

 We know that in the South Pacific, as well as on the 

 Asiatic coasts of our own latitude, they are exceed- 

 ingly abundant. 



The present indication, in relation to structure 

 and specific characters, is that they very closely re- 

 semble those of certain Atlantic types. That any 

 species will be found identical with those of the Atlan- 

 tic can perhaps scarcely be expected, but in some 

 quite accurate examination will be needed to sepa- 

 rate them. This is strikingly true in regard to the 

 one this evening exhibited and described. Itbi 

 to the genus Pentacta, {Cucumaria of Blainville, 

 Forbes and others) and so nearly represents P.fron- 

 dosa, Jaeg. in its general form and external charac- 

 ters, that it is at once taken for that species. Dissec- 

 tion and the microscope show, however, a structure 

 which in certain ] oints distinguishes it. That this 

 close representation should exist, is in itself a mat- 

 ter of no small interest, as bearing on the ques- 

 tion of geographical distribution, since P.frondosa 

 inhabits both sides of the Atlantic, being found not 

 only in the seas of western and northern Europe, but 

 also along the coasts of N. America, as far south at 

 least as Cape Cod, being very abundant about the 

 entrance of the Bay of Fundy. 

 • I first obtained it several years since, my speci- 

 mens having been taken on Georges Bank. I b 

 that time no European specimens of Holothuridae 

 ■with which to compare it, and was compelled to trust 

 entirely to descriptions and figures, the most com- 

 plete and apparently reliable being those by I 

 and Koren. 'Nothing could be found in these which 

 indicated the type in question, either specifically or 

 generically, and accordingly in a series of arti 

 the Holothuridae then in course ol publication, I in- 

 cluded a notice of it und.T the generic name Botryo- 

 dactyla, calling the species B. grandis (Proc. 

 S.N. H., April 16, 1861.) 



Subsequently specimens received from the distin- 

 guished naturalist Sars, "of Norway, with his own 

 labels attached, furnished material for direct com- 

 parison with true and authenticated European forms, 

 and it became at once evident that Botryodactyla 

 was entirely id -n ical with that which bore M. Sars' 

 label of Pentacta. But with these specimens before 

 me, it seemel much less remarkable that 1 should 

 have fallen into my previous error, than that ucb 

 characters should have been attributed to the genus, 

 especially th ise given by Duben and Koren. .' 

 pression like this, " anuulus calcareus oris gracilis 

 (nee snrsnm nee deorsum in longiorea processus pro- 

 ductus)," could in no way '• I to the Norwe- 



gian types which wen labelled Pentacta. Btill, M. 

 Sars' judgment in regard to the verification is an 

 authority which cannot he questioned, and as between 

 the European and American forms no differem 

 be traced, even on microscopic points of structure, 

 the name Botryodactyla must he a i, indoned, a 



merely an additional synonym of Pentacta ; and B. 

 grandis is simply P. J random. 



Of the 1'acilic form, representing this, we have as 

 yet seen only small specimens, none of them extend- 

 ing much over an inch in length These, however, 

 are manifestly immature, and as externally they sim- 

 ulate in every respect specimens of the Atlantic P. 

 frondosa, of the same size, it is reasonable to infer 

 that when full grown, they attain corresponding di. 

 mensions with the Eastern type. They differ from 

 the latter, in having the respiratory trees not so 

 largely developed, thoui,]i entirely the same in form 

 and structure, the alimentary canal much shorter 

 (Otherwise identical), aud the perforated calcareous 

 plates of the skin and of the suckers very much more 

 numerous, but retaining the characteristic appear- 

 ance. It is thus manifest that tne specimens lound 

 on this coast, vary from those of the Atlantic, not in 

 any definite characters, but merely in the extent of 

 those which are common to both. The form and ar- 

 rangement of the suckers, the tentacala, the oral 

 circle, and the entire organs of respiration, digest i i . 

 aud reproduction are absolutely the same in the two. 

 It is deemed, therefore, for the present, more pru- 

 dent to attempt no separation of the species. Adult 

 specimens may at some future time show that the 

 Californian type is distinct, but we willnot now incur 

 the risk of adding to the already overburdened list 

 of synonyms of P. frondosa. And we do this, not- 

 withstanding the very great improbability that any 

 s of the Echinodermata possesses so wide a 

 range as this claims for the Sea Pumpkin, as the 

 ichusetts fishermen call it. In a subsequent 

 paper, when speaking of the Star Fishes of this 

 coast, we may have occasion to ricur to this remark. 

 The whole series of the Holothurida: needs a thor- 

 ough revision, especially in regard to generic divis- 

 ions. Many of the names now in use are but syno- 

 n\ ins, and some which are perhaps good and true 

 genera, are so imperfectly defined as to be of little 

 practical value. Some of tho'se which have been 

 proposed by myself. lam now fully satisfied cannot 

 be maintained. Sclerodacttla (1'roc. Bost Soc. 

 Nat- Hist., vol. 4, p. G) is anticipated by Trosi ' 

 imperfectly characterized genus Axapeucs, .S'. brim 

 revs being only A. carolinus. Botktodactyla has 

 b§en alreadj mentioned. Mr. Stimpson, in a papejj 

 published in the Smithsonian Contributions, vol. 0, 



idcrs the genus Duasmodactyla proposed by me 

 (loc. cit. vol. 4, p. 244), identical with Thyonidium. 

 Thisscarcely appears to me possible. The d (-position 

 ■ tentacula we may disregard without bringing 

 the two in relation ; but the structure of the tentac- 

 ula, the calcareous deposites in the tentacula and 

 the other parts of the surface, the genital tubes divi- 

 de! in the one and undivided in the other, certainly 

 seem like characters of generic value. At alleveuts, 

 if any dependence can be placed on the description 

 by Duben .V Koren. Duasmodactyla producta is not 

 ■'closely allied to T. pellucidum." Thegenus comes 

 much nearer to TroschcTs division Orcu/a, but can- 

 not be included in the latter without a modification 

 of the limits given by its describer. 

 Species yet to be detected on this coast will, wc 



■ assist in giving us a better understand 

 both specific and generic divisions. 



Dr. Lanszweort was i hat d to fill the office ofCl 

 rator of Geology. 



San Francisco, Aug 27, 1855. 

 Col. Ransom in the Chair. 



Donations to the Cali 

 From Dr. Bebr, a specimen of the Cal. Silk Worm 



