IO 



Caribbean Sea, Guadeloupe, Dominica, between 611 and 1568 fathoms (A. Milne-Edwards) ; 

 West coast of Ireland, 610 — 982 fathoms (Selbie) ; Gulf of Gascony at depths of 355 — 655 

 fathoms (Caullery); Mediterranean (Senna); Eastern Atlantic (Bouvier); Cape Natal N. by E. 

 (approx.) 24 miles, 440 fathoms (Stebbing); Arabian Sea, 738, 824, 836 fathoms (Alcock). 



2. Stereomastis trispinosa (de Man). (PI. I, Fig. 1 — lö). 



Pentachcles trispinosus J. G. de Man, in: Tijdschr. Ned. Dierk. Vereen. (2) Dl. IX, 1905, p. 587. 



Stat. 38. April 1. 7°35'.4S., U7°28'.6E. 732—915 m. Bottom coral. 1 male of medium size, 



1 younger male and 4 younger females. 

 Stat. 45. April 6. 7°24'S., n8°is'.2E. 794 m. Bottom fine grey mud, with some radiolariae 



and diatomes. 1 young male. 

 Stat. 314. Febr. 17, 1900. 7°36'S., ii7°3o'.8E. 694 m. Bottom fine sandy mud. 1 female 



without eggs of medium size and 7 young specimens, 5 males and 2 females. 

 Stat. 316. Febr. 19, 1900. 7 19'.4 S., u6°49'.5E. 538 m. 1 adult female with eggs and 3 

 males, one of medium size and two young. 



Though closely related to Stereom. phosphorus (Alcock), Stereom. andamanensis (Alcock) 

 and other forms, I did not hesitate to describe this species as a new one, for it is distinguished, 

 besides by other characters, at first sight by the fact that the carinae of only the three first 

 abdominal terga are culminating in an antrorse spine, — from which character the specific 

 name is derived. 



The carapace of the adult female from Stat. 316 shows its greatest width in front of 

 the deep cervical groove : it is little more than two-thirds the length, the rostral spines included. 

 The carapace is a little less broad, in proportion to its length, than that of Stereom. phosphorus 

 and the antero-lateral angles are slightly farther distant from one another. Posterior to the 

 cervical groove, the lateral borders converge but very slightly backwards, like in Stereom. 

 phosphorus. Beneath the hairy tomentum, with which it is covered, the upper surface appears, 

 here and there, minutely granular, so especially on the branchial regions, less distinctly also 

 outside the orbital notches and on the gastric region. The frontal border is concave, like in 

 Stereom. phosphorus, the orbital notches have the same form, the same size and the same 

 direction with regard to the mid-dorsal line. In this specimen the acute tooth on the frontal 

 border of the eye-stalks is situated near the outer margin, for it is 3-times as far distant from 

 the inner border as from the outer border of the orbital notch; the tooth is directed upward 

 and outward. The frontal border, slightly concave between the orbital sinuses, makes almost 

 right angles with the oblique inner margins of the latter and carries at either angle a short 

 spine, which is directed upward, forward and slightly outward. The outer and the inner border 

 of the orbital notches run nearly parallel, their outer angle is rounded and unarmed ; the oval, 

 semitranslucent, not calcareous area at the posterior end of the eye-stalk is quite distinct, 

 situated as usual in a depression of the carapace. The upper surface of the carapace slopes 

 obliquely down from the median carina, which is its most elevated part, towards the lateral 

 borders, but the hepatic region, situated between the orbital sinus and the lateral border and 

 extending, gradually narrowing, from the frontal border until the cervical groove, is flattened 



