I Hi THE VOYAGE OF H.M.S. CHALLENGER. 



( >f this species two specimens have been collected. The measurements of the ore have 

 been already given, the length of the other specimen was only 27 mm. for the capitulum 

 and 12 mm. for the peduncle. 



1 have not studied the internal structure of this animal, but of the complemental males 

 I may give the following description. I got three of them, which I found attached between 

 the mantle and the left hand scutum, at a small distance from the apex. They are globular 

 and rather small; their length is about 1 mm. They are covered by a mantle, which 

 shows a very large slit, and which in the hindermost part of the body is confluent with the 

 wall of the body. This hindermost part forms a globular excrescence, and causes the little 

 male to look as furnished with a rudimentary peduncle. As rudiments of the prehensile 

 antennae, however, are present at the other extremity of the body, I think this com- 

 parison hardly admissible. The interior of the male is yet in an embryonic condition ; a 

 rather voluminous testis is present, but it is only just beginning to form spermatozoa, 

 and the receptaculum seminis is still very small. The contents of the body for the rest 

 consist of clear drops and of fatty corpuscles, which probably represent the remains of 

 the deutoplasm of the embryo. The surface of the mantle is covered with microscopic 

 spines, and the inner surface is beautifully striated. 



This species was taken at Station 246, July 2, 1875 ; lat. 36° 10' N., long. 178° 0' E. ; 

 depth, 2050 fathoms; bottom temperature, 1°"3 C. ; bottom, grey ooze. 



Observations. — This is one of those cases (referred to already p. 28) in which a 

 species was taken at a considerable distance from the shore, the Station, 246, being 

 situated almost in the middle of the Pacific Ocean. 



Scalpellum moluccanum, n. sp. (PL V. figs. 3, 4). 



Valves fourteen. Surface of the valves covered by a chitinous and almost smooth 

 membrane. Carina simply — not strongly — bowed, with the apex projecting freely, and 

 the roof not flat. Umbo of the carina at the apex. Upper latus almost triangular. 

 Peduncle middle-sized. 



This species much resembles Scalpellum regium (Wyv. Thorns.), n. sp., and is also 

 nearly related to Scalpellum velutinum, n. sp. It is represented by a single specimen 

 only, and as this is not in all respects a sound one, I have been long uncertain whether I 

 should describe it as a distinct species or not. 



The capitulum consists of fourteen valves; the relative straightness of the carina gives 

 the capitulum an oblong quadrangular appearance. The apex of the scutum projects freely 

 as well as that of the carina. The capitulum is rather stout, and, especially towards the lower 

 end, it is very thick. The valves are covered by a not very thick chitinous membrane, which 



