110 Cumaeea: 11. Diastylidae, 3. Diastylopsis 



j Fifth pleon segment decidedly longer than sixth ... 1. D. neozealanica 

 \ Fifth and sixth pleon segments differing little in length — 3. 



J Carapace encircled by transverse converging lines ... 2. D. dawsoni 

 \ Carapace without encircling lines — 4. 



(First pleon segment with prominent medio-veutral tooth, 

 without latere -ventral spines 3. D. elongata 

 First pleon segment without prominent ventral tooth, 

 with latero-ventral spines 4. D. crassior 



/ Telson longer than peduncle of uropods 5. D. annulata 



\ Telson not longer than peduncle of uropods — 6. 



Carapace shorter than the pedigerous segments combined 6. D. robusta 

 6 \ Carapace not shorter than the pedigerous segments 

 combined — 7. 



Third maxilliped with laminar distal expansion of 2nd 



joint 7. D. thileniusi 



n 



I Third maxilliped without laminar expansion of 2nd joint 8. D. dentifrons 



1. D. neozealanica (G. M. Thorns.) 1892 Diastylis n., G. M. Thomson in : J. Linn. 

 Sec. London, v. 24 p. 268 t. 18 f. 1 — 11 | 1908 Diastylopsis (?) neoseelandiae, Zimmer in: 

 Ergeb. Tiefsee-Exp., 1^.8 p. 190. 



Pseudorostral lobes not much produced, conical, somewhat arched in 

 dorsal outline, antero-lateral angle obsolete: carapace with eyelobe small or 

 wanting, dorsally having 4 transverse bars on the anterior half, the last 

 bilobed, and a fifth parallel to and near the hind margin. Pedigerous seg- 

 ment 4 the longest, its side-plates directed backwards ; postero-lateral corners 

 of the 5*^ produced obtusely backwards; fi^h ^^\qq^ segment considerably 

 shorter than the 5^^ and subequal to the telson, which is al)out Vgtiis ^s long 

 as the peduncle of the uropods and has 8 pairs of lateral spines on ,the 

 tapering distal half. Maxilliped 3 with long setae on the widened distal 

 end of the 2"^ joint, 3^ much wider than the small 4*ii joint. Peraeopod 1 

 very long, 2"«^ joint shorter than rest of limb, without strong teeth on medial 

 margin, 5^^ joint rather longer than 6^^ ii^^ than 7^1 ; peraeopod 2, 5«i joint 

 longer than 6*'^ and 7^^ combined; peraeopods 3, 4 without exopod (text) 

 but apparently with rudiment (Fig. 8, G. M. Thomson), and their presence 

 ascertained (Caiman). Endopod of uropods about half as long as the 

 peduncle, P* joint longer than 2"^, 2''^ than 3^, with 5, 4, 4, or 6, 3, 4 spines 

 on the joints respectively, the 2-jointed exopod a little longer. L. g 8 mm, 

 d unknown. 



New Zealand, Eay of Islands, depth 15 m. 



2. D. dawsoni S. I. Sm. 1880 D. d., S. I. Smith in: Rep. geol. Surv. Canada, 

 app. D. p. 215B I 1900 D. d., G. 0. Sars, Crust. Norway, v.'d p. 64 1 1908 D. d., Zimmer 

 in: Ergeb. Tiefsee-Exp., v.8 p. 183, 190 | 1912 D. d., Caiman in: P. U. S. Mus., vAl 

 p. 605, 662 tf. 81-90. 



Pseudorostral lobes well produced, horizontal, acute, autero-kiteral 

 corners acutely produced in g only; carapace slender, partly encircled anteriorly 

 by 4 pairs of fine lines, converging downwards, 1^* pair nearly meeting 

 some way in front of the small eyeless eyelobe, 2'^* ^nd 3'^ meeting the 

 sutures of the frontal lobe, which is crossed by lines to the rear of the 

 2 lateral pairs, the 4*^ pair not meeting dorsally; lower margin serrate for 

 a small distance anteriorly. Pedigerous segment 2 with side-plates defined 

 above by a notch, rounded in front, covering those of segment 1, in the d 



