176 Cumacea: 24. Nannastacidae, 3. Nannastacus, 4. Platycuma 



developed. In peraeopod 4 the development of the exopod-bearing 2^^ joint 

 is strongly contrasted with the slenderness of the following joints. Uropods 

 rather longer than in the 9 . 



Seas of Great Britain and Ireland, from north of Shetland to Plymouth; W. coast 

 of France: Mediterranean, Messina and Spezia, depths 11 — 19 m. 



16. N. stebbingi Calm. 1904 N. s., Caiman in: Herdman, Rep. Ceylon Pearl 

 Fish., r. 2 p. 159, 176 t. 5 f. 91—93. 



Near to N. ossiani (nr. 9), but with the last three pedigerous segments 

 carrying paired serrated crests on the dorsal surface. Here also immediately 

 below the pseudorostrum the concave antero-lateral margin bears a group of 

 three curved spines, of which the upper and largest is very conspicuous. These, 

 however, are perhaps also present in A^. ossiani. L. (S, 1-38 mm, 9 unknown. 



Gulf of Manaar; depth 4 m. 



Genus dubium et species dubiae 



Diops Paulson 1875 D., Paulson, Unters. Krebse rot. Meer., v. 1 p. 129 | 1879 

 Nannastacus, G. 0. Sars in: Arch. Naturv. Kristian., u 4 p. 108 | 1880 N., Kossmann, 

 Reise Roth. Meer., Malac. pars 2 p. 90. 



Probably a synonym of Nannastacus (p. 168), but (as described) distinguished by 

 a slender 3-jointed second antenna in the female, and by having only a single apical 

 filament on the palp of the first maxilla. 



Diops parvulus Paulson 1875 D. p., Paulson, Unters. Krebse rot. Meer., v. I 

 p. 129 t. 21 f. 1— Ir I 1880 D. (Nannastacus) p., Kossmann, Reise Roth. Meer., Malac. 

 pars 2 p. 90 | 1893 D. p., T. Stebbing in: Int. sci. Ser., u 74 p. 306. 



9. L. 3-5 mm, larger than any accepted species of Nannastacus, and impossible 

 to reconcile with N. unguiculatus, the apical lobes of the pseudorostrum not being 

 serrate, the antero-lateral corners little instead of much outdrawn and the margin below 

 little if at all serrate. The telsonic segment (as figured) differs from the accustomed form. 



Nannastacus spinosus (Paulson) 1875 Diops s., Paulson, Unters. Krebse rot. 

 Meer., f. 1 p. 131 t. 21 f . 2 | 1880 ? Nannastacus sarsii, Kossmann, Reise Roth. Meer., 

 Malac. pars 2 p. 90 t. 4 f. 4—9, t. 5 f. 1. 



Kossraann's species, ^, 2-75 mm long, has 2 filaments on the palp of the first 

 maxilla, Paulson's specimen, only 1 mm long, was evidently not dissected. Both authors 

 represent the 5tli segment of the spinose pleon as uncommonly short. 



4. Gen. Platycuma Caiman 



1905 Platycuma (Sp. un.: P. holti), Caiman in: Sci. Invest. Fish. Ireland, 1904 

 app. 1 p. 3, 30 I 1912 P., T. Stebbing in: Ann. S. Afr. Mus., v. 10 v p. 164, 171. 



Carapace depressed and expanded, overhanging the anterior pedigerous 

 segments. Pedigerous segments except the first laterally expanded. Telsonic 

 segment short. Eye wanting. Alimentary canal spirally coiled. Mouth-organs 

 generally as in Cumellopsis (p. 177), but first maxilla with single filament to 

 the palp, epipod of first maxilliped with a single branchial leaflet. 



Female unknown. 



1 species. 



1. P. holti Calm. 1905 P. h., Caiman in: Sci. Invest. Fish. Ireland, 1904 app.l 

 p. 10, 3(J I 1912 P. h., T. Stebbing in: Ann. S. Afr. Mus., v. lOv p. 131. 



Integument pellucid. Pseudorostral lobes slightly upturned meeting 

 before the frontal lobe for one-eighth the length of the carapace, not as far 



