MUSEUM OF COMPARATIVE ZOOLOGY. 3 
prove not to be of specific value. But considering the differences which really 
exist with regard to the outer appearance, and taking into consideration, 
that the deposits were dissolved in the types brought home by the Chal- 
lenger expedition, I propose to refer it, for the present at least, to a new 
species. 
The Blake specimen differs from Benthodytes sanguinolenta in being devoid 
of the transverse ventral row of papille situated immediately behind the 
crown of tentacles; the position of the anus is more ventral, and it carries 
only a very few slender dorsal processes, which seem to be confined to the two 
ambulacra alone. The madreporic canal appears to open exteriorly (?). The 
integument is rather rough from numerous larger and smaller deposits, which 
consist of four curved arms and a smooth central spine directed outwardly ; 
each of the four arms generally bears a large process directed outwardly and a 
few smaller ones. In the ventral perisome, the deposits are more irregularly 
formed, and have the shape of unbranched rods and three- or four-armed bod- 
ies. Thus the deposits of this species closely resemble those of Euphronides 
depressa. 
Habitat. Bequia; depth 1591 fathoms. One specimen, 220 mm. long and 
53 mm. broad. 
Benthodytes sp. (2). 
The very defective state of the specimens at my disposal renders a detailed 
examination impossible. They seem to bear the closest resemblance to Bentho- 
dytes abyssicola. There appear to be fifteen tentacles. The dorsal ambulacral 
appendages are few and minute. The deposits present themselves as scattered, 
very large and robust four-armed spicules with a long spinous central spine, 
the extremity of which is usually split into two or three spinous tops, giving 
to the surface of the skin a remarkable roughness. The central spines are 
almost visible to the naked eye. 
Habitat. Bequia; depth 1507 fathoms ; three very incomplete specimens. 
Pelopatides Agassizii, n. sp. 
One of the largest specimens has the following measurements: length 
270 mm.; breadth 120 mm.; height varying between 5 and 10 mm. The 
body is thus very depressed, almost flat, and very broad; its anterior and 
posterior ends are obtusely rounded or truncated. The pedicels are only 
present on the odd ambulacrum, where they form a thin double row over three 
fourths of its length; the anterior fourth of the odd ambulacrum is naked. 
The thin wide brim, which surrounds the body and reaches a breadth of about 
40 mm., is pierced by a number of canals which branch off from the two 
ventral lateral ambulacra, cross the brim, and run out in very minute papille 
situated in the margin of the brim. These papille form a simple row in 
