ANCEUS. CRUSTACEA. 177 



Gen. 18. ANCEUS, Risso. 



Four antennae, the exterior longest, and terminated by setaceous 

 joints ; head of the males with two projections like mandibles ; 

 body oblong, depressed, of five segments ; the first two very 

 broad, furrowed, and united ; ten monodactyle feet, the last 

 four directed backwards ; tail terminated by two laminae and 

 a pointed intermediate one. 



A..forficularis } Risso. Body whitish. 2 lines long. Found near Nice, 

 in deep water, in the interstices of madrepores. Risso, Crust, pi. 

 2, fig. 10. 



Gen. 19. PRANIZA, Leach. Oniscus, Mont. 

 Four unequal setaceous antennae ; body elongated, of three seg- 

 ments, the last largest, and bearing the last three pairs of feet ; 

 abdomen or tail of six segments, terminated by four elonga- 

 ted, oval, and ciliated laminae. 



P. ccerulata, Desm. Body bluish. 1J or 2 lines long. Inhabits Bri- 

 tish coasts Desm. Crust. 284. 



FAMILY IV. HETEROPA. 



With all the feet (fo'urteen) or at least the last four, proper for 

 swimming. 



Gen. 20. APSEUDES, Leach. Eupheus, Risso. 

 Four antennae, the two external longer than the intermediate ; 

 body elongated, formed of six joints ; abdomen or tail elon- 

 gated, conical, of about fifteen segments ; the two anterior 

 feet didactyle ; the last four directed backwards, ciliated, and 

 proper for swimming. 



E. Ugioides, Risso. Body elongated cylindrical, flattened above and 

 concave below ; head truncated before ; body varied with yellow, 

 white, and greenish. 2 lines long. Inhabits Mediterranean coasts, 

 among marine plants Risso, Crust, pi. 3, fig. 7- 



E. talpa, Desm. Head pointed ; body above with three longitudi- 

 nal divisions ; last joint of the antennae plumose ; abdomen hairy. 

 Inhabits British seas. Lin. Trans, ix. pi. 4, fig. 6. 



Gen. 21. IONE, Lat. Lam. Oniscus, Mont. 

 Antennae subulate and short ; body ovoid, obtuse before, of one 

 segment ; abdomen short, of four transverse segments, and 

 terminated by two long claviform appendages similar to feet ; 

 feet without nails, spatulous ; diminishing in length poste- 

 riorly. 



I. thoracicus, Lam. Spurious feet below the abdomen ciliated. In- 

 habits European seas. B. Lin. Trans, ix. pi. 5, fig. 3. 



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