18 THE VOYAGE OF H.M.S. CHALLENGER. 



It needs no comment that it is at the least rather hazardous to identify with the 

 Mediterranean species (which seems also to have been examined and figured by Quatre- 

 fages when he gave the description of his Cerebratulus crassus), a specimen in which the 

 proboscis, as well as its armature, is absent. Still the transverse sections offer such a very 

 close resemblance to those of actual specimens of Drepanophorus serraticollis, that it 

 would be again hazardous to establish a new species for the fragments, of which the colora- 

 tion affords a less decisive clue than in the case of the foregoing Drepanophorus rubro- 

 striatus — the madder-brown hue referred to by M'Intosh being all that is preserved of 

 the uniform though bright coloration which the specimen must have had when alive, if 

 it agreed in this respect with the Mediterranean Drepanophorus serraticollis. 



I have, moreover, hazarded the identification with the foregoing specimens of a third 

 fragment collected in the Kerguelen waters, of which not only the proboscis but also the 

 head was absent. Here, too, the internal characters enabled me to refer the specimen 

 to the genus Drepanophorus (the transverse cseca of the proboscidian sheath being in 

 this case the guiding feature). 



The systematic position of this specimen thus only rests upon the similarity of the 

 transverse sections and on the general yellow hue of the fragment, darker on the dorsal 

 than on the ventral surface. 



The very thick- walled proboscidian sheath with its delicate lateral sacs, different in 

 certain respects from that of a new species of Drepanophorus hereafter to be described, is 

 figured on PI. X. fig. 5. 



Drepanophorus lankesteri, n. sp. (PI. I. fig. 22; PI. IX. figs. 1, 2, 10; PL X. figs. 

 2, 4 ; PL XII. figs. 5 ; PL XIV. figs. 9, 10 ; PL XV. fig. 13). 



Of the three species of Drepanophorus contained in the Challenger collection, this is 

 without doubt in several respects the most remarkable. One specimen measuring 30 

 mm. in length and 3^ mm. in breadth was obtained ; it was dredged at Station 49, in 

 the waters of Nova Scotia. As to its colour when alive, the spirit specimen allows of 

 no other certain conclusion than that the dorsal surface is darker than the ventral, which 

 may have been whitish. No special markings are now traceable on the dorsal integument, 

 and we may thus surmise that its natural colour, which has been only partly preserved 

 in spirit, was in life brown or red. 



If I nevertheless feel justified in creating it a new species, it is because certain internal 

 characters are so well marked as to allow of no confusion with the species of Drepano- 

 phorus hitherto known. 



The two characteristic features which immediately attract attention in studying a 

 series of sections through this species are, first, the presence of a series of transverse 

 commissures (PL IX. fig. 10) metamerically placed at intervals of about 0"2 to 0'15 mm., 

 and connecting the two longitudinal nerve-stems all along their course below the intes- 



