410 



CRUSTACEA. 



outer maxillipeds, enlarged two diameters ; c, last joint of anterior 

 legs. 



Valparaiso. 



The rounded median tooth of the front appears to be a constant 

 character of this species. The inner apex of the third joint of the 

 outer maxillipeds is produced, but is quite short, and the anterior 

 margin of the last joint of the anterior legs has a small acute tooth to- 

 wards the articulation. The prolongation of the apex of both the 

 penult and antepenult joints, in these legs, is less than in the emerita. 



Ifi'ppa tafpoida, SAY, Jour. Acad. Nat. Sci., i. 160; GIBBES, Proc. Meeting of Amer. 

 Assoc. at Charleston, 1850, p. 188. 



SUBTRIBB V. PORCELLANIDEA. 



THE Porcellanidea pertain to a single genus Porcellana. Edwards, 

 in his corresponding division, " Porcellaniens," embraces also the 

 genera ^Eglea and Megalopus, yet expresses his doubts with regard to 

 such an arrangement. The genus ^glea belongs properly to a lower 

 grade of the Anomoura than Porcellana, inasmuch as the inner an- 

 tennae are posterior to the eyes, and, therefore, fall into our lowest 

 section of the Anomoura. the Anomoura inferiora. The genus Mega- 

 lopus has little actual relation to the Porcellanidea. 



GENUS PORCELLANA. 



The carapax in the genus Porcellana varies much in form and 

 markings. The front is usually more or less triangular, and when 

 straight in a view from above, there is often, if not always, a triangular 

 outline when observed in a front view, so that the straight margin, in 

 such cases, is owing to the front being deflexed. Tlu> surface may 

 be entirely smooth. But commonly the front and posterior margin of 



