106 MODERN SYSTEM. 



Cancer Phasma. Montagu, Trans. Linn. Soc. vii. 66. t. G.f. 3. Leach, 

 Supp. to Envycl. Brit. i. 4Q6. 



Inhabits the southern coast of Devon. 



Astacus atumos of Pennant and Squilla lohutu of Miiller belong to the 

 genus CaprcUa, of which in the British Museum there arc several 

 tindescribed species. 



Stirps 2. Bodij broad. 



Genus 1(5. LARUNDA. Leach. Cyamus. Latr., Bosc. Paxope. 

 Leach. 



Antenna four-jointed, upper ones longest: /cgs compressed, with strong 

 cla\\^s ; the third and fourth pairs elongate, spurious, cylindric, with- 

 out claws; the two anterior pairs monodaclyle. 



External uterus, or pouch of the female, composed of four valves. 



Sp. 1. Lar. Cetl Bases of the third and fourth pairs of legs with pro- 

 cesses resembling the figure 6; the hands of the second pair of legs 

 anteriorly, with three obtuse teeth. 



Oniscus Ceti. Linn. Si/st. Nat. i. lOGO. Pall. Spec. Zool. ix. 4. /. 11. 

 Squille de la Baleine. Be Geer, Man. surks Insect. Vn.pl. 42./. (3, 7. 

 Pycrogonum Ceti. Fubr. Supp. Ent. Syst. 570. Cyamus Ceti. Latr. 

 Gen. Crust, et Lisect. i. 60. Panope Ceti. Leach, Edin. Enct/cl. vii. 

 404. Larunda Ceti. Leach, Trans. Linn. Soc. xi. 36-k.— Supp. to En- 

 ci/cl. Brit. I. 426. pi. 21. 



Inhabits whales, and according to Latreille it is also found on some 

 sjiecies of the genus Sco)nher. 



By the Greenland fishermen it is termed the Whale-louse. 



Fani. IV. Idotead.e. Leach. 



Both/ with all the segments not bearing legs : {ventral appendages co-, 

 vered by two longitudinal plates.) 



Genus 17. IDOTEA. Fubr., Latr., Bosc, Leach. Asellus. Ohv., 

 Lamarck. Extomon. Klein. 

 External antenna; half the length of the body, or less; the tliird and 



fourth joints equal : body ovate. 

 Sp. 1. LI. pelagica. Body linear-oval: tail roimded, tlie middle, with a 

 very obsolete tooth: antenna^ one third of the length of the boily. 

 Idotea pelagica. Leach, Trans. Linn. Soc. xi. 365.— Supp. to Encijcl. Brit. i. 



426. 

 Inhabits the Scottish seas. 



Colour when alive ash-gray or fuscous, speckled with darker co- 

 lour, and often variegated or mottled with white spots : legs pale. 



The female seems to be very rare, as amongst 400 specimens of 

 the animal, one only of that sex was found. 

 Length one inch and a (piarter. 



