FISHERY BULLETIN: VOL. 85, NO. 2 



orbital) dor sally concave, rather strong; gastro- 

 orbital carina blunt but well defined; antennal carina 

 relatively short, and branchiostegal-hepatic carina 

 strong and sharp only anteriorly. Orbito-antennal 

 sulcus quite shallow; hepatic sulcus not fusing with 

 branchiocardiac sulcus and extending posteriorly, 

 almost longitudinally rather than turning ventral- 

 ly, subparallel to anterior part of branchiocardiac 

 sulcus; branchiocardiac sulcus and accompanying 

 carina long, extending posteriorly to near margin 

 of carapace. 



Eye with optic calathus relatively long, length of 

 mesial margin 1.4 times distal width; mesial tuber- 

 cle situated almost at midlength. 



Antennular peduncle with stylocerite produced in 

 sharp spine reaching mesial base of distolateral 

 spine; latter small and sharp; third article in females 

 not expanded laterally; dorsal and ventral flagella 

 incomplete. 



Scaphocerite long, conspicuously surpassing 

 antennular peduncle; strong lateral rib ending in 

 sharp spine falling considerably short of distal end 

 of lamella. Antennal flagellum incomplete. 



Geographic and bathymetric ranges.— Pseudaristeus 

 speciosus is known only from the type-locality. 



Discission.— This species, tentatively assigned to 

 the genus Pseudaristeus, can be readily distin- 

 guished from the other members of the genus in 

 possessing an anterolateral carina; the branchios- 

 tegal-hepatic carina is strong and sharp only ante- 

 riorly; the ventral extremity of the cervical sulcus 

 is almost straight, instead of turning anteroventral- 

 ly, and is accompanied by a very weak, rather than 

 sharp, and strongly arched carina; also the posterior 

 part of the hepatic sulcus extends subparallel to the 

 branchiocardiac sulcus instead of fusing with it 

 before turning ventrally. 



Pseudaristeus speciosus was described from 2 

 specimens, one of which is no longer extant and the 

 other has disintegrated except for the anterior part 

 of the carapace to which are attached the eyes, 

 antennules and antennae, and the dismembered 

 distal part of the third maxillipeds. Despite the poor 

 condition of the available syntype, the distinctive 

 features of the carapace, which are clearly repre- 

 sented in Bate's (1888) illustration of the entire 

 animal, are sufficient to conclude that P. speciosus 

 is a valid species. Because the branchiae of the syn- 

 type are lacking, it is not possible, as noted by 

 Crosnier (1978), to determine with certainty the 

 genus to which it should be assigned, but because 

 of the supraspecific characters exhibited by the 



carapace, I am almost convinced that it is congeneric 

 with the five Indo-West Pacific species studied 

 herein. 



It should be noted that the syntypes of P. speci- 

 osus were found at 4,847 m, a depth considerably 

 beyond the greatest depth, 1,785 m, at which any 

 of the assumed relatives are known to occur. 



ACKNOWLEDGMENTS 



Without the generous cooperation of various 

 colleagues this study would not have been possible. 

 I am much indebted to Maya Deb of the Zoological 

 Survey of India for providing descriptions, drawings 

 and photographs of certain morphological features 

 of the lectotype of P. crassipes, which permitted a 

 confirmation of the true identity of the species, and 

 for the loan of critical collections from the waters 

 off India; to Alain Crosnier of the Office de la 

 Recherche Scientifique et Technique Outre Mer and 

 the Museum National d'Histoire Naturelle for his 

 hospitality during a working visit to the latter in- 

 stitution, for the loan of specimens, and for review- 

 ing the manuscript; and to Anthony A. Fincham of 

 the British Museum (Natural History), H.-E. Gruner 

 of the Zoologisches Museum de Humboldt Univer- 

 sitat, and S. Pinkster of the Zoologisch Museum, 

 Amsterdam, for providing materials, including 

 types, from their respective institutions; to H. C. 

 Ghosh of the Zoological Survey of India for a draw- 

 ing of the antennular peduncle of the lectotype of 

 P. crassipes. Horton H. Hobbs, Jr. of the Smith- 

 sonian Institution once again offered invaluable ad- 

 vice and innumerable suggestions during the course 

 of my studies and preparation of the paper; Fenner 

 A. Chace, Jr. aided me in solving technical problems 

 and commented on the first draft; Bruce B. Collette 

 and Austin B. Williams of the National Marine Fish- 

 eries Service Systematics Laboratory critically read 

 the manuscript. Keiko Hiratsuka Moore, with her 

 artistic talent and devotion to accuracy, made all the 

 illustrations except those of the eyes of various 

 species and the gnathal appendages and of the 

 carapace of P. kathleenae which were rendered by 

 Maria M. Dieguez. Ruth E. Gibbons prepared the 

 map. Virginia R. Thomas and Arleen S. McClain pa- 

 tiently typed several drafts of the manuscript. To 

 all of them goes my deep gratitude. 



LITERATURE CITED 



Alcock, a. W. 



1898. A summary of the deep-sea zoological work of the royal 

 Indian Marine Survey Ship "Investigator" from 1884 to 



336 



