116 Cumacea: 11. Diastylidae, 4. Adiastylis 



than the 2"*^^ or 3*^, with 3, 2, 2 spines respectively on the medial margin. 

 L. 9 juv. nearly 10 mm. d unknown. 

 Bay of Biscay, depth 650 m. 



3. A. longipes (0. Sars) 1871 Diastylis l, (r. 0. Sars in: OtV. Ak. Forh., j;.28i 

 p. 74 1 1871 D. l, (jr. 0. Sai-s in: Svenska Ak. Handl., n. ser. w.9 nr. 13 p. 32 1. 13 f. 65- 67 j 

 1879 D. l, A. M. Norman in: Ann. nat. Hist., ser. 5 ». 3 p. 58 | 1896 D. l, J. Bonnier in: 

 Ann. Uuiv. Lyon, ». 26 p. 550 t. 29 f. 4a— p | 1912 Adiastylis I, T. Stebbing in: Ann. 

 S. Afr. Mus., V. 10 V p. 148. 



Pseudorostral lobes moderately produced in advance of the small eyeless 

 eyelobe, horizontal, acute, with a subapical pair of spinules, antero-lateral 

 angles obsolete; anterior part of carapace with several variously disposed 

 spinules; 1^*^ pleon segment with ventral longitudinal crest of 4 or 5 con- 

 spicuous teeth, h^^ and Q^^ segments subequal, telson rather longer than 

 both combined, and longer than peduncle of uropods, the narrowed distal 

 part short, with 4 pairs of lateral spines and a small apical pair. Antenna 1 

 elongate, 2"*^ joint of peduncle much longer than 3^, principal flagellum long, ■ 

 6-jointed, accessory stout, 3-jointed. Mandibles with 16 or 17 spines in the 

 spine-row. Maxilliped 3, with a strong spine on the 2"'^ and also on the 

 A:^'^ joint. Peraeopod 1 extremely long, especially in regard to the last 

 3 slender joints, of which joint 6 is" actually longer than the 2''^ joint. Peraeo- 

 pod 2, h^^ joint more than twice as long as the ^^^ and 7*^ combined in 

 the 6 (G. 0. Sai*s), 1^"^ very short (G. 0. Sars), not very short in the 9 (Bonnier). 

 Peraeopods 3, 4, 4*^ joint more or a little less than twice as long as the 

 3 following joints combined. Rudimentary exopods on these limbs not recorded 

 for 9 juv. Peduncle of uropods much longer than the rami, endopod with 

 pt joint longer than 2°*^ and '6^ combined, spines on medial margin respectively 

 12 or 13, 5, 4; exopod little longer than 1^* joint of endopod. L. 6 juv. 

 about 8 mm, 9 juv. 12 mm. 



Atlantic: Lat. 600 45' ^.^ long. 4° 49' W., 933 m; lat. 59° 41' N., long. 7*> 34' W., 

 838 m; lat. 38'> T N., long. 9" 18' W., 1036 m; Bay of Biscay, depth 950 m. 



4. A. COStatus (Bonnier) 1896 Diastylis costaia, J. Bonnier in: Ann. Univ. Lyon, 

 u26 p. 553 t. 30 f. 1, 1 a— m, o | 1912 Adiastylis costatus, T. Stebbing in: Ann. S. Afr. 



Mus., V. lOv p. 148. 



Pseudorostral lobes acute, slightly raised. Eyeless eyelobe very small, 

 behind it runs a median serrate crest, bifurcating about the middle of the 

 carapace, the 2 arms reaching the hind margin; more or less oblique to the 

 median are 4 pairs of curved crests, and spinules are irregularly dispersed 

 in the intervals. Pedigerous segments 3—5 with transverse rows of spinules; 

 pleon segments 1—5 with longitudinal rows; telson distally with 5 lateral 

 pairs and an apical pair. Antenna 1 with 4 spines on P* joint, 3'^ joint 

 longer than 2"^ principal flagellum 4-, accessory 2-jointed. Antenna 2 4-jointed, 

 3d joint the longest. Mandible with 12 spines in the spine-row. Peraeo- 

 pod 1, 2"'^ joint very long. Peraeopod 2, the long slender 5"» joint more 

 than twice as long as 6"^ and 7^^ together, 7*^ twice the 6*^. Peduncle of 

 uropods shorter than the telson, but much longer than the exopod; exopod 

 a little longer than the endopod, the 1 ^* joint of which nearly equals the 2°^ 

 and 3^ together, with 2, 2, I spines on the medial margin of the 3 joints 

 respectively. L. 9 juv. 6 mm. 



Bay of Biscay, depth 1410 m. 



