364 Dr. Lracn’s Arrangement of the Crustacea, óc. 
| 
Spec. 1. Larunda Ceti. 
Oniscus Ceti. Linn. Syst. Nat. i. 1060. 
Squille de la Baleine. De Geer, Mém. sur les Ins. vii. pl. 42. F-6.7. 
Pycnogonum Ceti. Fabr. Suppl. Ent. Syst. 610. 
Cyamus Ceti. Latr. Gen. Crust. et Ins. i. 60. 
Panope Ceti. Leach, Edin. Encycl. vii. 404. 
‘Habitat in balenis (etiam in scombris, Latreille). 
DIVISIO I. 
. Corpus segmentis omnibus haud pedigeris ; segmentum ultimum 
caudz maximum. Antenne filiformes, medi: brevissimze, ex- 
 teriores ad corporis dimidium longitudinis et ultra. Ungues 
validi. i 
Gen. 18. Iporza. 
Antenne exteriores dimidium aut minus corporis longitudinis 
eequantes, articulis tertio quartoque aequalibus. Corpus ovatum. 
Spec. 1. Idotea Entomon. 
I. corpore elongato-ovato, caudá apice tridentatä: dente inter- 
medio majore, antennis nere corporis longitudinem fere 
eequantibus. 
Oniscus Entomon. Linn. Syst. Nat. i. 1060. 
Penn. Brit. Zool. iv. pl. 18. fig. 5. 
Habitat in mari Britannico passim inter fucos. 
Color cinereus, fusco-punctatissimus, seepe cremore maculatus, 
This species, which is very common on all our rocky coasts, va- 
ries much in the form of the extremity of the tail, often occurring 
without the lateral teeth, which is ever the case (as far as I have 
examined) in younger specimens. Oniscus marinus of Pennant, 
plate xviii. fig. 3, appears to be the variety above mentioned. 
Length one inch and a quarter. | 
s Spec. 2. 
