P^CILOPODA. 151 



Some of them whose feet are free, and (the two last excepted) 

 annexed to the anterior part of the body — Cephalothorax, Lat. — 

 covered by the shield, in which some of the posterior feet are fur- 

 nished with numerous and pennated threads, and in which the si- 

 phon is not apparent, have the abdomen naked above and termi- 

 nated by tv/o long; threads, or as many stylets; they compose the 

 subgenus 



Caligus, properly so called. — Caligus risculus, Leach(l). 



In all others, the superior surface of the body is imbricated, or 

 that portion of the body is enclosed in a kind of case formed by the 

 last feet which resemble membranes and fold over it. 



Of these latter, there are some whose antennae never project like 

 little claws, whose feet are free, and whose last ones do not envelope 

 the body like a membranous case. They form the following sub- 

 genera. 



Pterygopoda, Lat. — Nogaus? Leach. 



Where the posterior extremity of the body is terminated by two 

 kinds of finsj where the under part of the post-abdomen or of the 

 second division of the body, not covered by the shield, is furnished 

 with pinnated or digitated feetj and where there is a distinct pro- 

 boscis or rostrum(2). 



Pandarus, Leach. 



Two threads at the posterior extremity of the body; the first and 

 fifth pairs of feet unguiculated, and the remainder digitated; no ap- 

 parent siphon(3). 



DiNEMOURA, Lat. 



Two long anal filaments and an apparent siphon; the two anterior 

 feet unguiculated; the two following ones terminated by two long 

 toes, and the remainder membranous leaflets(l). 



no mistake in this ? I have studied these same organs in various specimens — pre- 

 served in spirits, it is true — but could never discover any body whatever. 



(1) Caligus piscinus, Lat.; Cal. curtus, Miill. Entom., XXI, 1, 2; Monoculus pis- 

 cinus, L.; Cal. Mullen, Leach; Desmar., Consid., L, 4; found on the Cod. The 

 Oniscus lutosus, Slabber, Encyclop. Method., Atl. d'Hist. Nat. CCCXXX, 7, 8, 

 from the fin-like appendages of its tail, seems to indicate a separate subgenus. The 

 Binocle ^ queue en plumet, Geoff., might be placed in it. 



(2) A single living species found on the Shark. See the genus Nogaus, Des- 

 mar., Consid., p. 340. 



(3) Pandarus bicolor, L«ach; Desmar., L., 5; Pandarus Boscii, Leach, Encyc. 

 Brit. Suppl. I, XX. For the otlier species, see Desmar., lb., p. 339. 



(1) Caligus produdus, Miill., Entom. XXXI, 3, 4; Monoculus sahnoiieun. Fab. 



