Jan. 3, 1878] 



NATURE 



185 



THE '"CHALLENGER" IN THE ATLANTIC^ 



II. 



T T still seems but the other day when every zoologist 

 ■*• believed with Edward Forbes that not very far below 



the surface of the sea there existed a region where life 



was unknown, or where at the most, if it existed it showed 



but a few sparks, which only served " to mark its lingering 



presence ;" and yet even when Forbes 



was writing thus, Sir John Ross had 



brought up from some 800 fathoms 



deep in Baffin's Bay, "a beautiful 



Caput meduscE^ and the present pre- 

 sident^ of the Royal Society had 



written (August 31, 1845), " It is prob- 

 able that animal life exists at a very 



great depth — in the ocean." "On 



one occasion, off Victoria Land, be- 

 tween the parallels of 71° and 78° 



S.L., the dredge was repeatedly em- 

 ployed, once with great success at 



380 fathoms," and " on another occa- 

 sion the sounding-line brought up 



distinct traces of animal life from a 



depth of 550 fathoms." The history, 



hoivever, of the subject, is to be found 



recorded in Sir Wyville Thomson's 



" Depths of the Sea," and we only 



here refer to it to remind the reader 



how completely changed are the 



general ideas on this subject ; and 



we learn without surprise that ** the 



most prominent and remarkable bio- 

 logical result of the Challenger's 



voyage is the final establishment of 



the fact that the distribution of living 



[animal] beings has no depth limit, 



but that animals of all the marine 



invertebrate classes, and probably 



fishes also, exist over the whole of 



the flora of the ocean ; " but although 



life is thus universally extended, 



probably the number of species as 



well as of individuals diminishes 



after a certain depth is reached; 



This distribution of animal life de» 



pends in a marked degree either upon 



the nature of the sea-bottom or upon 



the conditions which modify the 



nature of that bottom. The fauna 



at great depths was found to be 



remarkably uniform, and the distri- 

 bution area seemed to depend mainly 



on the maintenance of a tolerably 



uniform temperature. It is curious- 



to note that the families which are 



peculiarly characteristic of the abyssal 



fauna, contain a larger number of 



species and individuals, and these 



are larger and more fully developed 



in the Antarctic Ocean, than they 



are in the Atlantic and the North 



Pacific. 

 Though the task of determining 



the various animal forms procured 



will occupy a number of specialists for several years, 



still we have several glimpses of the riches of the ocean 



' " The Voyage of the Challenger. The Atlantic : a Preliminary Account 

 of the General Results of the Exploring Voyage of H.M.S. C/iallenger 

 d-mng the Year 187? and the Early Part of the Year 1876." By Sir C. 

 WyviUe Thomson, KnL. LL.D., F.R.SS. L. and E., &c., Regius Professor 

 of Natural History in the University of Edinburgh, and Director of the 

 Civilian Scieniific Staff of the Challenger Exploring Expedition. Two 

 volumes. Published by Authority of the Lords Commi-sioners of the 

 Admiralty. (London : Macraillan and Ca, 1877.) Continued from P. I48. 



* Sur Joseph Hooker, C.B. 



fauna in these two volumes. Among these the pretty 

 Hexactinellid sponges, the stalked crinoids, and the echi- 

 noids seem to hold foremost places. The stalked crinoids 

 with their lily-like forms are the most remarkable of 

 these, not only on account of their extreme rarity, but 

 also on account of the special interest of their relation to 

 many well-known fossil forms. Of one of these fine forms 

 we give the accompanying illustration (Fig. 3). It was 





Fig. 3. — Pentactinus maclearanus, Wyville Thomson. Slightly enlarged. 



dredged from a depth of about 400 fathoms, near the 

 Island of San Miguel. It belongs to the genus Penia- 

 crinus, and has been called after Capt. Maclear, R.N-., 

 the commander of the Challenger. The lily-shaped head 

 is about 3^ inches in height, and the stalk may have been 

 several inches longer. The scientific descriptioji of such 

 a form must necessarily be very technical, and not easily 

 to be understood by the general reader, who, however, 

 cannot fail to get a correct idea of its general form and 



