Cumacea: 11. Diastylidae, 4. Adiastylis 



115 



J ) Pedigerous segments dorsally dentate 1. A. acanthodes 



\ Pedigerous segments not dorsally dentate 2. A. longicaudatus 



^ I Exopod of uropods much shorter than the endopod . . 3. A. longipes 



I Exopod of uropods not shorter than the endopod 



4. A. costatus 



1. A. acanthodes Stebb. 1912 A. a., T. Stebbing in: Ann. S. Afr. Mus., 

 V. 10 V p. 148 t. 53. 



With points of resemblance to Diastylis anomalus (p. 106). 



Pseudorostral lobes well produced acutely in advance 

 of the eyeless eyelobe, forming an obtuse angle with the 

 curved medio-dorsal line of the carapace, their upper surface 

 like the rest of the carapace diversified with many unequal 

 denticles. Pedigerous segments much denticulate, the last 4 

 each with a pair of dorsal teeth specially conspicuous, the 

 first 2 each with front margin serrate. Pleon longer than 

 anterior part of the body, with dorsal and some subventral 

 denticles, 5*^ segment much longer than 6*^, but shorter than 

 the telson, which is about ^1^^^ as long as peduncle of uropods, 

 its last third narrow, with 3 or 4 pairs of lateral spines and 

 a larger apical pair. Antenna 1, principal flagellum 5- (or 6-) 

 Jointed, accessory 4-jointed. Antenna 2, 2°'^ and 5^^ joints 

 of pedimcle long, flagellum comparatively short. Maxilliped 3, 

 2"*^i joint with long setae on the dilated end, none of the other 

 joints dilated. Peraeopod 1, 2°'^ joint denticulate. Peraeo- 

 pod 2, with tooth at apex of the short stout 2°*^ joint, 5*^ 

 and 7*ii joints long and slender, 7*^ more than twice as 

 long as the 6*^. Peraeopods 3 and 4 with 2^"^^ joint striking- 

 ly narrowed distally. Pleopods 1 considerably longer than 

 the 2°*^ pair. Peduncle of uropods much longer than exopod, 

 which is little longer than the first 2 joints of the endopod, 

 2^<i joint of endopod ^j/^ the length of the 1^\ 3'^ joint 

 missing from the specimen. L, d about 9 mm. Q unknown. 



S. Africa, Cape Natal N. by E. 24 miles, depth 805 m. 



2. A. longicaudatus (Bonnier) 1896 Leptostylis longicaudata, 

 . I. Bonnier in: Ann. Univ. Lyon, v. 26 p. 557 t. 30 f. 2, 2a— o | 1908 

 Diastylis I., Zimmer in: Ergeb. Tiefsee-Exp., v.8 p. 183 | 1912 Adi- 

 astylis longicaudatus, T. Stebbing in: Ann. S. Afr. Mus., r. lOv p. 148. 



Pseudorostral lobes acutely produced, antero-lateral cor- 

 ners faintly marked, not produced; carapace besprinkled with ^'^- '"■ 

 spinules, medio-dorsal line of frontal lobe slightly undulating; steMrin8^°tisS 

 pedigerous segments and pleon not dentate, S*^'' segment of and uiopod. 

 pleon not much longer than others, telson shorter than peduncle 

 of the uropods but much longer than the rami, the short distal section carrying 

 3 pairs of lateral spines and a larger apical pair. Eye quite wanting. An- 

 tenna 1, 3*^^ joint of peduncle not longer than 2°*^, principal flagellum 4-jointed, 

 accessory 3-jointed, very short. Antenna 2 of 4 joints, the 1^^ the longest. 

 Peraeopod 1 very long, 7^^ ^qI^\^ .^ YiUXq longer than the 6*^; peraeopod 2, 

 o^^^ and 7*^ joints not very long, 7^^ only twice as long as the G*'^. Perae- 

 opods 3 and 4 with 2-jointed rudimentary exopods. Exopod of uropods 

 notably longer than the endopod, of which the P* joint is not much longer 



8* 



