MEGALOPIDEA. 493 



the posterior half, near posterior margin, a transverse depression. 

 The long setae of the posterior tarsi are nearly twice as long as the 

 tarsi. The other tarsi are depressed, and sparsely fringed on the 

 margin with short hairs; those of the anterior margin as long as the 

 diameter of the tarsus, and those of the posterior, about half this 

 length. 



This species is exceedingly near the Monolepis inermis. In that 

 species, however (see fig. 6, Plate 31), the anterior pieces of the ster- 

 num (s) bordering the sternal fossa have the inner margin triangu- 

 late, and the following piece either side (t) has a prominent tubercle 

 on the surface. Moreover, the small prominence (r), at the middle 

 of the sternum, between the buccal area and the sternal fossa, consists 

 of three subordinate tubercles, two more anterior than the other. In 

 the figure referred to, b, is the buccal area in outline, the parts within 

 being omitted ; p, the prominence either side behind the orbits, not 

 seen in an upper view. 



Genus CYLLENE, Dana. 



Carapax fronte simplicissime rostratus, rostro vix deflexo. Pedes 8 pos- 

 tici ad basin infra uni-spinigeri. Pedes 6ti 4:tis parce minor es, depres- 

 sione carapacis ad eos recipiendos parce concavd, tarso lamellate-, versus 

 apicem elongate setigero. 



Carapax with a simple beak in front, and beak hardly deflected. 

 Eight posterior feet at base below armed with a short spine, tarsi 

 unarmed. Feet of fifth pair a little shorter than the preceding ; the 

 depression of the carapax for receiving the legs slightly concave ; 

 tarsus lamellar, long setigerous towards apex. 



This genus is very close to Leach's Megalopa, but is peculiar in the 

 lamellar posterior tarsi. 



Ctllene hyalina. 



Rostrum parce prominens. Carapax subovatus, pyne oculos marginibus 

 paulo saliens, postice inermis. Ceplialoihorax infra postice inermis. 



124 



