Cumacea: 11. Diastylidae, 6. Paradiastylis, 7. Leptostylis 123 



in 9 in accord with well developed exopod. Peraeopods 1 — 4 with 2°^ joint greatly 

 expanded and distally produced. Endopod of uropods with 6, 3, 3 spines on 

 the 3 joints respectively, the 3 *i joint longer than the 2"^*. L. Q 3 mm, d 3-5 mm. 

 Sulu Archipelago, surface to 32 m; (julf of Siani, depth 9—18 m. 



7. Gen. Leptostylis 0. Sars 



1869 Leptostylis, G. 0. Sars in : Nyt Mag. Naturv., ul6 p. 343 | 1893 L., T. Stebbing 

 in: Int. sci. Ser., u 74 p. 311 | 1900 L., G. 0. Sars, Crust. Norway, v.B p. 67 | 1900 

 L., Zimmer in: Fauna arctica, v.l p. 427, 431 | 1908 L.. Zinimer in: Ergeb. Tiefsee- 

 Exp., r. 8 p. 181,182 | 1911 L., Caiman in: Tr. zool. Soc. London, t). 18iv p. 366, 367 j 

 1912 L., T. Stebbing in: Ann. S. Afr. 3Ius., v. 10 v p. 129, 152. 



In general agreement with Diastylis, but having a shorter telson, with 

 lateral spines few or none; postero-lateral angles of fifth pedigerous segment 

 not acute: eye wanting; first antenna of female with second joint of peduncle 

 the shortest;" first peraeopod usually long: third and fourth pairs in female 

 with rudimentary exopods: pleopods of male with short rami; exopod of 

 uropods generally shorter than the endopod. 



11 species. 



Synopsis of species: 

 ) Uropods with exopod not shorter than the endopod . . 1. L. mancus 

 i Uropods with exopod shorter than the endopod — 2. 

 ) Pedigerous segments 1, 2, emarginate in front — 3. 

 I Pedigerous segments 1, 2, not emarginate in front — 5, 

 I Lateral ridges enclosing cordiform area on front of carapace 2. L. antipus 

 \ Carapace without such ridges — 4. 



j Carapace sparsely hirsute, lower margin acutely serrate 3. L. ampullaceus 

 \ Carapace closely hirsute, lower margin squarely serrate 4. L. villosus 

 I Uropods with 1st joint of endopod equal to the 3d — 6. 

 \ Uropods with 1st and 3d joints of endopod unequal — 7. 

 , Carapace about thrice as long as pedigerous segments 



combined • 5. L. crassieauda 



\ Carapace not nearly thrice as long as pedigerous segments 



' combined 6. L. borealis 



j Uropods with 1st joint of endopod shorter than 3d — 8. 

 I Uropods with 1st joint of endopod longer than 3d — 9. 



f Carapace with lower margin acutely serrate 7. L. macrurus 



\ Carapace with lower margin squarely serrate 8. L. macruroides 



) Uropods with exopod not longer than 1st joint of endopod 9. L. productus 

 ^ \ Uropods with exopod much longer than 1st joint of endopod — 10. 

 / Uropods with 1st joint of endopod at least as long as 



J 2nd and 3d combined 10. L, longimanus 



\ Uropods with 1st joint of endopod little longer than 



1 2nd or 3d ... ILL. gracilis 



1. L. mancus 0. Sars 1873 L. manca, G. 0. Sars in: Svenska Ak. Handl., n. ser. 

 vAl nr. 5 p. 21 t. 5 f. 24-28 ] 1902 L. m., Zimmer in: Ergeb. Hamburg. Magalh.- 

 Sammelr.. i'. 2 Cumac. p. 8 tf. 11— 14 | 1905 L. m., Caiman in: Sci. Invest. Fish. 

 Ireland. 1904 app. L p. 40 | 1908 Diastylis 'm., Zimmer in: Ergeb. Tiefsee Exp., v.8 

 p. 183 I 1912 Leptostylis mancus, T. Stebbing in: Ann. S. Afr. Mus., v. lOv p. 153. 



Pseudorostral lobes shortly and bluntly produced, forming no distinct 

 antero-lateral corner. Carapace roughly pentagonal in dorsal aspect, antero- 

 lateral margin denticulate; with denticles crossing the frontal lobe and the 

 pseudorostral lobes, from which on either side a subdorsal denticulate crest 



