524 Dr. A. Alcock — ^I Revision 



I have examined the specimens in the British Museum. 

 This genus contains the single species : — 



Xiphopeneus Kroyeri (Heller), SB. k. Akad. Wiss. Wien, 1862, xlv. B, 

 Abth. i. p. 425, pi. ii. fig. 51. ( = X. Harttii, Smith, Amer. Journ. 

 Sci. xlviii. 1869, p. 390, and Trans. Connect. Acad. ii. 1871, p. 28, 

 ]il. i. fig. 1.)— Brazil; W. Indies. 



8. Atypopexeus, gen. nov. 



nostrum toothed dorsal ly only. Antero-inferior angles of 

 carapace rectangular. Postantennular sulcus not defined at 

 all. No longitudinal or transverse carapacial sutures. 



Antennular fagella much lunger than the carapace. Endo- 

 podite of maxillules slender. Filamentous exopodites on all 

 the thoracic legs, 



Epipodites absent from third maxillipeds and last two 

 pairs of thoracic legs. No pleurobranchise on the last two 

 thoracic somites. 



The andricum is symmetrical. 



Type, Peneus covipressipes, Henderson, Trans. Linn. Soc, 

 Zool. (2) V. 1893, p. 450, pi. xl. figs. 21, 22. 



As Henderson surmised, this is a unique form and is 

 worthy of a separate position. 



This genus or section includes, at present, only Henderson's 

 Peneus compressipes ; but two of Stimpson's species from 

 Hongkong, viz. P . podophthalmus and P. stenodactylus, may 

 possibly be assigned to it, 



9. Sedis Incert.e. 



1. Peuevs villosus, Guerin, in Voy. ' Coquille,' vol. ii. Zool., Crust, p. 36; 



and Icon. Kegne Anim, pi. xx. fig. 1. — Austi-alia. Probably a 

 Metapenetis, as the figure shows ventral edge of rostrum smooth, 

 foliaceous exopodites, and no carapacial sutures. 



2. Peneus foliaeeus, Kisso, Hist. Nat. Eur. merid. v. 1826, p. 69, pi. ii. 



fig, 6. — Mediteri-anean. Probaoly a Parapeneus, as the figure 

 shows no exopodites to the thoracic legs, 



3. Peneus tenuis, Dana, U.S. £xpl. E.xp., Crust, pt. i. p. 605, pi. xl. fig. 6, 



— Atlantic coast of Patagonia. JPosition quite uncertain, except 

 that it does not belong to Peneus (s. r.). 



4. Peneus stenodactylus, Stimpson, Proc. Acad. Xat. Sci. Philad. 1860, 



p. 43. — Hongkong. Appears to be very closely. related to P. com- 

 pressipes, Henderson, the type of the section Atypopeneus. 



5. Peneus podophthalmus, Stimpson, loc.cit. — Hongkong. Also seems to 



resemble P. comp7-cssipes even more than does P. stenodactylus. 



6. Peneus novce-guinece, Ilaswell, P. L. S. N, S. Wales, 1879, p. 43 ; and 



Cat. Austral, Crust, p. 203. — New Guinea. Differs from other 

 Penei in not having a hepatic spine. 



