CRUSTACEA. 647 
Sp. Bopyrus squillarum Latr., Monoculus Crangorum Fasr., LATREILLE 
Gen. Crust. ec Ins. Tab. 1. fig. 4, fem., GUERIN Iconogr., Crust. Pl. 29, 
fig. 1, RatHKE de Bopyro, Tab. 1. This little animal (the male is at most 
t4 lines long, the female 5 lines) lives under the dorsal shield on the gills of 
Palemones; on the Crangones, so nearly allied to them, and often living in 
the same situation, this Bopyrus as it seems does not occur (RATHKE). The 
fishermen think that these parasites are young soles (Plewronectes solea L.) 
Phryxus RAtHKE. Branchiez exsert, bilobed, in four pairs. 
Sp. Phryxus Hippolytes RatHKE Beitrage zur Fauna Norwegens, Tab. 11. 
figs. I—10, pp. 40—56. This little animal, not different from Bopyrus 
abdominalis KRoEYER (Tidsskrift, 11. 1840, pp. 102—112, 289—299, Tab. 
I. 11.) keeps to the ventral surface of Hippolyte. The full-grown female has 
on one side only a single foot which is attached to the first segment, whilst 
on the other side, as is usual, seven feet are found.—Phryxus crangonis 
RatHKE, ibid. Tab. 1, figs. 13—15, Tab. 1. figs. 11, 12. 
Tone Larr. Branchial feet in six pairs, exsert, filiform, arbor- 
escent in female. 
Sp. Oniscus thoracicus Montaau, Transac. of the Linn. Soc. Vol. 1X. p. 103, 
Pl. 3, figs. 3, 4, Desmar. Crust. Pl. 46, fig. 10, Gutrin Iconogr., Crust. 
Pl. 46, figs. 1, 2; compare also AUDOUIN and Minne Epwarps Ann. des 
Se. nat. Tom. 1x., EDwarps Hist. nat. des Crust. Pl. 33, figs. 14, 15. This 
species lives on the gills of Callianassa subterranea. 
Kepon Duvernoy (Cepon). Feet unarmed, with last joint sub- 
dilated. Abdominal feet with pinnated branchie. 
Sp. Cepon typus, DuvERNoY Ann. des Sc. natur. 2e Série, Tom. xv. 1841, 
Zoolog. pp. 110—122, Pl. 4, B, figs. r—11. 
Family XV. Cymothoadea. Head small. Mandibles furnished 
with a large palp. Feet of trunk in seven pairs, either all or the 
anterior terminated by a hook incurved and moveable. Body oval, 
depressed. Posterior part of abdomen or tail composed of from 
three to six segments, with last segment (pygidium) large, scutiform. 
Feet of caudal segments lamellose ; feet of last pair terminated by 
two oars or oval styles, exsert on each side near the pygidium. 
Comp. the article Cymothoadées by W. E. Lracu, Dictionnaire des 
Sciences natwr. XII. pp. 338—354. 
Cymothoa Far. Antenne short, inserted under the exsert 
frons. Eyes two, lateral, situated at the margin of head. Seven 
pairs of feet; feet terminated by a hook incurved and moveable, 
bent and hidden under the trunk. 
