CLASS I. CRUSTACEA. g3 



eyes not thicker than their beading-backward peduncles : oi-hits above 



with one fissure. 

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



bifid; the sides tridentate. 

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



Herbst,\. 195. t. 12. f. T2. male. Cancer personatus. Herhst, 193. 



t. 12.,/: 71. female. Alburnea dentata. Fabr. Snpp. Ent. Si/st. 398. 



Bosc, Hist. Nut. des Crust, ii. 4. Corystes dentatus. I^itr. Corystes 



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

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



thrown up after heavy gales of wind. 



Genus 2. ATELECYCLUS. Leach, Lutrcille. 

 Hitimal antenna half the length of the body; the third segment com- 

 posed of elongate and cylindric joints: external douhk putpi with the 

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

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

 le^s of the male longer than the liody, with a compressed hand : 

 other legi witl» tibiie and tarsi of equal lengths, furnished with elon- 

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

 naked, rounded and sharp, the hinder unes obscurely subcoinpressed : 

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

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

 its extremity, the apex nearly straight; the fourth subquadrate, with 

 the anterior angles produced ; fifdi tlask-shaped, with a very sharp 

 extremity; of tlie 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 graiudate-margined : eyes 

 narrower than their footstalks ; orbits behind \\i\h. two fissures, be- 

 low, with one, 

 Sp. 1. At. heterodon. Shell granulated, the sides wiih 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, Mulac. Podoph. Brit. tub. 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 \\ ell known by the name of Old Mans Fact 

 Crab. 



Fam. II. PoRTUNiD^. Leach. 

 Antenna moderate, simple: hinder pair of legs with compressed claws. 



Genus 3. PORTUMNUS. Leach. 

 Eyes not thicker than their peduncles: orbits entire: unttrior pair of 

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

 base dilated :JlJlh pair with a compressed, foliaccous, lanceolate cla>\ . 



