ANOMOURA PORCELLANIDEA. 4X1 



the median region are distinct, the former being seen in a small trans- 

 verse elevation adjoining the medial line, and in a line with the post- 

 orbital angles. There is generally an angle in the lateral margin a 

 short distance behind the orbit, where there is sometimes a small 

 spine, and this angle is in many species the termination of a depressed 

 line, which passes inward and backward to the posterior limit of the 

 median region, the whole evidently corresponding to the depression so 

 common in Grapsus, and observed, also, in Eriphia; it appears to ter- 

 minate just posterior to the first or second normal tooth (tooth D or 

 E). In a few species there is a transverse depression in a line with 

 the posterior side of the median region, as in our figures of the P. 

 tomentosa and rnonilifera, especially in the former, and this depression 

 terminates normally just anterior to tooth S. Rarely, as in the spini- 

 frons, the surface is still more divided ; the median region shows the 

 intramedial areolet distinct from the extramedial, and is even sub- 

 divided partly into three parts in the usual way ; moreover, some of 

 the anterolateral areolets are distinct. The system of areolets in the 

 Porcellanse, is evidently the same as in the Cancroidea. The sides of 

 the carapax may be either rounded without a margin, or thin margi- 

 nate; and the margin may be entire, denticulate, or even spinulous in 

 part, the last being the case in the P. arrnata. 



The characters of the mouth and other organs are given in Ed- 

 wards's work on Crustacea, and need not be repeated. One of the 

 most remarkable peculiarities is the position of the outer antennae, 

 posterior and exterior to the eyes. The species live under stones 

 along sea-coasts, near low-tide level, also in cavities among corals, &c. 



1. Frons superne visus recte transversds, non trtangulatus. 

 PORCELLANA BIUNGUICULATA. 



Parce transversvs, valde convexus et subglobosus, Icevis, f?vnte supernh 

 viso recto. Pedes antici mediocres, carpo elongato, plus duplo lon- 

 giore quam lato, integro, Icevi, manu Icevi, obsolete punctata, digitis 

 rnanus majoris valde Mantibus, superiore bene arcuato. Pedes se- 

 quentes nudi, torso brevi, verticaliter valde bhmguiculato [spnnd ungiii- 

 culatd vix breviore quam unguiculum verum infra imtrvcto) . 



A little transverse, very convex and subglobose, smooth ; front as seen 

 from above straight. Anterior feet of moderate size; carpus more 



