Cumacea: 10. Diastyloididae, 1. Diastyloides, 11. Diastylidae 



D. biplicatus, A. M. Norman in: Ann. nat. Hist., ser. 6 v. 13 p. 276 | 1897 D. biplicata, 

 T. Scott in: Rep. Fish. Board Scotl., v.lo p. 134 | 1900 Diastyloides h., G. O. Sars, 

 Crust. Norway, v. 3 p. 62 t. 46 | 1900 D. b., Zimnier in: Fauna arctica, v. I p. 426 (with 

 synonymy) | 1905 D. b., Caiman in: Sci. Invest. Fish. Ireland, 1904 app. 1 p. 5^ 



48 I 1909 D. b., A. M. Norman & U. S. 



Brady in: Nat. Hist. Tr. Northumb., 



ser. 2 v.3n p. 33. 



Pseudorostral lobes well pro- 

 duced, slightly upturned, antero- 

 lateral corners obsolete. Carapace 

 with 2 pairs of lateral oblique 

 carinae, and hind margin also cari- 

 nate, with an infero-lateral carina 

 added in the d, only anterior half 

 of lower margin serrate. Telson 

 shorter than peduncle of uropods, 

 with 6 pairs of lateral spines, 

 geniculate in d at about one-third 

 of its length. Peraeopod 1 elongate,, 

 especially in regard to the 6^^^ joint, 

 which is as long as the 2'^'^. Peraeo- 

 pod 2 with both 2'i'i and 3^^ joints 

 produced to a spiniform apex. 

 Peduncle of uropods in the female 

 little longer than the endopod. which 

 exceeds the exopod by its 3*^ joint 

 or more, spines on medial margin 

 of its 3 joints respectively in Q 9, 

 2, 1, in d 20, 4, 2. Colour tinged 

 with reddish brown. L. 9 7 mm. 

 d about 8 mm. 



Norway, with D.serratus; Skagerrak and Kattegat; round Scotland; N. E. England,. 

 71— 82 m; off W. of Ireland, depth 220— 2980 m. 



Fig. 54. 

 D. biplicatus (Sars), peraeopod 1. 



11. Fam. Diastylidae 



1856 Diastylidae, Bate in: Ann. nat. Hist., ser. 2 t).17 p. 449 ] 1859 D., Danielssen 

 in: Norske Selsk. Skr. 19. Aarh., j;.4ii p. 108 | 1863 D., A. M. Norman in: Tr. Tyneside- 

 Club, V. 5iv p. 271 I 1864 D., Fr. Miiller, Fiir Darwin, p. 55 | 1878 & 1879 D. (restricted), 

 G. 0. Sars in: Arch. Naturv. Kristian., v. 3 p. 466; «). 4 p. 44 | 1887 D., G. O. Sars in: 

 Rep. Voy. Challenger, v. 19 pars 55 p. 7, 43 | 1893 D., T. Stebbing in: Int. sci. Ser., 

 ?;. 74 p. 311,312 | 1900 D., C. 0. Sars, Crust. Norway, v.3 p. 41 ] 1900 D., Zimmer in: 

 Fauna arctica, v. I p. 420, 433 | 1908 D., Zimmer in: Ergeb. Tiefsee-Exp., 1.8 p. 181 | 

 1911 D., Caiman in: Tr. zool. Soc. London, i).18iv p.342,366 [ 1912 D. (further restricted), 

 T. Stebbing in: Ann. S. Afr. Mus., vAOv p. 133, 146, 



Of the pedigerous segments the first and usually the rest distinct. Telson 

 well developed, with only two apical spines. Accessory flagellum of first 

 antenna distinct, mandibles normal, not broad at the base. Palp of first 

 maxilla with two filaments. Branchial leaflets numerous. Exopods on the 

 first two pairs of peraeopods. also on the third and fourth pairs in the male 

 but not in the female, except occasionally as rudiments. Two pairs of pleo- 

 pods in the male. Uropods with the endopod three-jointed. 



8 genera accepted. 



