CLASS I. CRUSTACEA. 83 



eiics not tliicker than their bending-backward peduncles: orUts above 



with one fissure. 

 Sp. 1. Cor. cassivelaunus. Shell granulated, crenulated behind; front 



bitid ; the sides tridentate. 

 Cancer cassivelaunus. Fenn. Brit. Zool. iv. 6. t. 7. male and female. 



Herbsf, i. 195. t. VI. f. 72. male. Cancer personatus. Hcrbst, 193. 



t. 12. /: 71. female. Alburnea dentata. Fabr. Supp. Ent. Sj/st. 398. 



Busc, Hist. Nat. dcs Crust, ii. 4. Corystes dentatus. Lntr. Corystes 



cassivelaunus. Ixach, Malac. Podoph. Brit. t. 1. 

 Inhabits most of the sandy shores of the European ocean, and is often 



thro^^^l up after hea\'j' gales of wind. 



Genus 2. ATELECYCLUS. Leach, Latrcille. 



External antenna: haU'the length of the body; the third segment com- 

 posed of elongate and cylindric joints : extei-nal double palpi witti the 

 second joint of the internal footstalk shortest, with the internal apex 

 produced, and the internal side notched towards the joint: anterior 

 legs of the male longer than the body, with a compressed hand : 

 ot/ier legs with tibia? and tarsi of equal lengths, furnished with elon- 

 gate, quadrate nails that are longitudinally sulcated, having their tips 

 naked, rounded and sharp, the hinder ones obscurely subcompressed : 

 abdomen of the male with the first joint transverse, linear, twice the 

 length of the second ; the third much elongated, narrower towards 

 its extremit}-, the apex nearly straight; the fourth subquadrate, with 

 the anterior angles produced ; fifth llask-shaped, with a very sharp 

 extremitv-; of the female, with the first five joints transverse qua- 

 drate, anteriorly notched ; the last elongate, subtriangular behind, 

 subproduced : shell subcircular, the sides gradually converging into 

 an angle behind ; hinder part truncate and granulate-margined : eyes 

 narrower than their footstalks ; orbits behind with t^vo fissures, be- 

 low, with one. 



Sp. 1. At.hcterodon. Shell granulated, the sides with seven serrulated 

 teeth, and other smaller teeth between some of the other teeth : 

 front with three serrulated teeth, the middle of which is the largest. 

 Leach, Malac. Podoph. Brit. tab. 2. 



This elegant crab was discovered by Montagu on the southern 

 coast of Devon, where it is not an uncommon species in deep water. 

 To the fishermen it is well known by the name of Old Man's Face 

 Crab. 



Fam. II. PoRTUKiD^. Leach. 



Antennte modersLte, simple: hinder pair of legs with compressed claws. 



Genus 3. PORTUMNUS. Leach. 

 Ei/es not thicker than their peduncles : orbits entire : anterior pair of 

 legs equal : other legs wkh compressed claws, internally towards their 

 base dilated -.ffih pair with a compressed, foliaceous, lanceolate claw : 



F 2 



