588 Aora. Microdeutopus 



has a dense brush of setae, whereas generally it is smooth; the Prolongation of 

 the 4*^ Joint, the relative leugths of öt^^, 6*^ and finger are very variable, but 

 how far the proportions are constant is as yet indeterminate. In A.gracilis ö 

 the 2*^ Joint of the 5^^ peraeopod is widened near the distal end, while in 

 the O , and perhaps in both sexes of some forms, it is oblong oval without 

 such widening. The telson is sometimes longer than broad (A.trkhohostrycUus), 

 nearly as broad as long (A.gracilis, A.kevgueleni), usually with the apex obtusely 

 angular, but sometimes (-4, gracdis Della Valle, not Sars) emarginate. Colour 

 whitish or greyish, with speckling. L. 8 mm (A. gradlis). 



North-Atlantic with adjoining seas (Europe), Pacific (South-Araerica, Austialia, 

 !New Zealand), southern Indian Ocean (Kerguelen Island). 



3. Gen. Microdeutopus A. Costa 



1853 Microdeutopns (Sp. un.: M. gryllotalpa). A. Costa in: Rend. Soe. ßorbon., 

 n. ser. v. 2 p. 171 | 1876 M., A. Boeck, Skand. Arkt. Ampiiip., v. 2 p. 564 | 1888 M., 

 T. Stebbing in: Rep. Voy. Challenger, u29 p. 299, 1711 i 1893 M., A. Della Valle in: 

 F. El. Neapel, r.20 p.410 | 1894 M., G. Ü. Sars, Crust. Xorway, v.l p.539 | 1856 Lembos 

 (part.), Eate in: Rep. Brit. Ass., 3Ieet. 25 p. 58 | 1857 L. (part.), Bäte in: Ann. nat. 

 Hist., ser. 2 z;. 19 p. 142 | 1859 Autonoe (part.), R. M. Bruzelius in: Svenska Ak. Handl., 

 n. ser. v.S nr. 1 p. 23 | 1862 Stimpsonia (Sp. un.: S. chelifera) (non 0. Girard 1853, 

 JSTemertini!) -(- Microdeutopus (part.) (Microdeuteropus) (Microdentopus Bäte), Bäte & 

 Westwood, Brit. sess. Crust., vA p. 284, 287 | 1869 Microdeuteropus (part.), A. M. Norman 

 in: Rep. Brit. Ass., Meet. 38 p.281 | 1874 ilf., T. Stebbing in: Ann. nat. Hi.st., ser. 4 

 vAi p. 12 I 1893 Stimpsonella, A. Della Valle in: F. Fl. Neapel, u.20 p.421. 



Body slender. Head with lateral lobes usually obtuse. Side-plate 1 

 in ö often produced forward, 2^ or 3^ the deepest, remainder successively 

 shallower. Antenna 1, 2"^ Joint the longest, accessory flagellum distinct. 

 General character as in Aora, but gnathopod 1 in cJ with 4*^ Joint not greatly 

 produced, 5**^ very bulky, its hind margin produced to a tooth, which with 

 belp of 6*^ Joint and finger makes the limb complexly subchelate. 



10 species accepted, 1 doubtful. 



Synopsis of accepted species: 



f Gnathopod 2 in (J, palm defined by a tooth — 2. 

 } Gnathopod 2 in (J, palm not defined by a tooth — 3. 



1 Gnathopod 2 in (5. 6tli Joint much shorter than ötli 1. M. chelifei' .... p. 589 

 { Gnathopod 2 in cj, 6tli Joint not shorter than 5tli 2. M. armatus . . . . p. 589 



{Gnathopod 1 in (5, tooth of 5tli Joint with accessory 

 tooth or teeth — 4. 

 Gnathopod 1 in cj, tooth of 5th joint simple — 8. 



/ Gnathopod 1 in (5, 5tli Joint with more than 1 

 J accessory tooth — 5. 



j Gnathopod 1 in <3, öth Joint with only 1 accessory 

 y tooth — 6. 



{Gnathopod 1 in (J, Sth joint with innermost tooth 

 the largest 3. M. gryllotalpa . . p. 590 

 Gnathopod 1 in c?, 5th joint with middle tooth 

 the largest 4. M. stationis . . . p. 590 



( Gnathopod 1 in (S, 5tli Joint with inner tooth the 



smaller 5. M. haswelli' . . . p. 591 



I wn 



the smaller — 7. 



) Gnathopod 1 in cS, 5th Joint Avith outer tooth 



