2i6 CRUSTACEA MALACOSTRACA. III. 



West of the Faeroes: Stat 44: Lat. 6i42' N., Long, cffl W., 545 fath., temp. 4-8; a specimen of 



Pleuroprion hystrix G. O. S. which has the marsupium filled with eggs, 

 and the male (or larval) parasite was found with its posterior part of the 

 body uncovered, while its anterior part was penetrating the front end of 

 the marsupium. 



AstacilloechuS n. gen. 



Immature Female. Body (fig. 33) oblong, a little more than twice as long as deep, about 

 from the middle tapering considerably to the first thoracic segment and much to the subacute end of 

 the abdomen; furthermore, the body is much curved and divided by conspicuous constrictions and 

 furrows into twelve segments; the animal is somewhat similar to the limbless larva of an Insect. Seen 

 from the side, the major upper part of the front margin of the animal is somewhat deeply concave, 

 as the lower part of first segment protrudes as a rounded portion. Seen from below (fig. 3 b) the first 

 segment is nearly three times as broad as long, with the anterior margin long and nearly straight 

 towards the broadly rounded antero-lateral angles, while its lower surface is broadly excavated longitudin- 

 ally, and in the median line at the base protrudes a somewhat small semiglobular body, which must 

 be the head and has a thin and at least two-jointed antenna at the side, but some chitinous strips on 

 the head I was unable to interpret. The thoracic segments without any vestige of legs; the uropods 

 quite inconspicuous. 



Male. In all features similar to that of Arcturocheres, excepting that the posterior part of 

 the inner margin of first joint of the antennulee has six acute teeth. 



Remarks. The female with the male were found in the marsupium of a specimen of Asta- 

 cilla granulata taken together with the specimen infested with Arcturocheres pulchripcs. While the 

 female differs so much from that of Arcturocheres that one might be tempted to place them in different 

 subfamilies, the males of the two forms differ only in small particulars, the most essential being the 

 number of teeth on first joint of the antennulae. This is, in my opinion, most remarkable. Unfortun- 

 ately I had only a single and, judging from the contents, far from mature female of each of the two 

 genera, and my investigation is most unsatisfactory, but I found it impossible to arrive at better re- 

 sults. And I thought it advisable not to omit either of the two forms, but to communicate my obser- 

 vations, so that they might serve future investigators, who may have a rich material of deep-sea forms 

 of Astacilla and allied genera, as a help and warning in the look out for the Cryptoniscidse. 



155. Astacilloechus Ingolfi n. sp. 

 (PI. XVI, figs. 3 a-3d). 



Immature Female. Nothing is to be added to the generic description, excepting that the 



animal measured along the middle of the side is about 3-5 mm. long, consequently of considerable size. 



Male. Very similar to the male of Arcturocheres pulchripes in size, shape, antennae, epimera, 



