488 
CRUSTACEA. 
This tnoe contains the genera, 11. Pilumnus ; 12. Cancer; 
13. Pirimela; 14. Atelecydus; 15. Podopbthalmus; 16. Lupa; 
17. Portunus; 18. Thia; 19. Portumnus. 
Genus 11. — PILUMNUS.— Leach. 
Generic Character. — With setaceous exterior antennae, which 
are long, slender, and inserted in the internal canthus of the 
eyes ; third joint of the exterior feet-jaws nearly square, sub- 
transverse, and notched towards the end; feet of the second, 
third, fourth, and fifth pairs terminated by simple nails; shell 
transverse, posteriorly truncated, the anterior margin semicircu¬ 
lar ; peduncles of the eyes thicker than the eyes. 
Pilumnus hirtellus. — The Hairy Pilumnus. 
Plate XCIII. fig. 6. 
Shell with five teeth on each side; body and legs thickly fur¬ 
nished with bristles ; claws muricated on the outside. Inhabits 
the Devonshire coast. 
Genus 12. — CANCER.— Linnceus. 
Generic Character. —With short exterior antennae inserted be¬ 
tween the inner canthus of the eye in front, and the interme¬ 
diate ones in small furrows in the centre ; third joint of the 
outer feet-jaws nearly square, with a notch at the internal angle 
of the summit; fore-feet largest, with unequal forceps; shell 
short, transverse, posteriorly narrowed; the front margin semi¬ 
circular, frequently dentated on the sides, with obtuse lateral 
angles ; eyes seated in a short peduncle. 
Cancer pagurus. — The Common Pagurus. 
Plate XCIII. fig. 8. 
With a granulated shell, having nine folds on each side ; front 
trilobate. Inhabits the European seas. 
Genus 13.—PIRIMELA. — Leach. 
Generic Character. —Exterior antennae inserted in the mtti- 
nal canthus of the eyes, the intermediate ones in oblique grooves 
of the hood ; exterior feet-jaws, with their third joint square, 
truncated, and nearly notched at its extremity on the inner side ; 
forceps equal; the other feet with sharp claws; shell subtrans- 
