144 DEEP SEA FISHES. 



Such depths to the northward as have been dragged with more thorough- 

 ness appear to liave swarmed with Brotuloids. The definitely ascertained 

 distribution of the group includes the Atlantic in the entire northern 

 portion and southward off the coasts of Brazil to the Straits of Magellan, 

 the Pacific in the Panamic region both sides of the northern portion and 

 the southwestern part, off Australia, and New Guinea, and the northern 

 extensions of the Indian Ocean. In the vertical ranges the greatest depths 

 yet obtained lie in the northern Atlantic at 2500 fathoms where the 

 species Mivomts lafcrcdis Giint., and Bassoxcius tcenia Glint., were taken by 

 the " Challenger," and Alexeterion Parfaiti Vaill., at 2736 fathoms by the 

 "Talisman." The "Challenger's" greatest depth for these fishes in the 

 Pacific was that of Tijphlonus mmis Glint., northeast of Australia at 2440 

 fathoms. The greatest depths recorded by the " Investigator " were those 

 of Neohi/thites pterotus Ale, and Dcrmatorns melunocephahis Ale., in the Bay 

 of Bengal at 1748 fathoms. In tlie present material of the " Albatross " 

 from the Galapagos section the deepest bottom appears in tlie case of 

 Holcomyderonus digittatus, a new species of a new genus, at 2232 fathoms. 

 There is reason to believe some of the young Brotuloids begin life nearer 

 the surface. 



Habitually tlie Brotuloids rest on the mud of the sea bottom, like the Lyco- 

 doids and as also in the cases of the latter, this habit has led to obsolescence 

 of the ventrals until the usefulness of these fins as means of progression is 

 completely at an end and they remain in many instances only as compara- 

 tively insignificant organs of touch. As seen in the group the various modi- 

 fications of the ventral fin range from the two distinct filamentary rays to 

 the two rays bound together, the single bifid ray, the single simple filament, 

 and the entirely obsolete. Aside from these Holcomyderonus possesses vent- 

 rals each of which is composed of two separated rays, the distal ends of 

 which are so expanded that tliey resemble small oars. In the pectorals 

 likewise a variety of modification has obtained. U.seful in balancing and in 

 making quick rushes ahead or back, in all cases these fins are at least moder- 

 ately developed. Though the fin is of the normal shape in the greater num- 

 ber of the genera, it takes on peculiar forms in others ; thus on Nematonus, 

 Mixonus, Dicrolene, and Pteroidonus from one to ten of tlie lower rays are 

 separate elongate and enlarged as if for tactile purposes, on Sciadonus the 

 carpalia are elongate and the fin is placed at the end of an arm, and on 

 Eretinichthys the lower half of the fin is much enlarged, lengthened, and 



