290 CRUSTACEA. 



Arek&us cribrarius, (Lamlc.) Dana. 



Plate 18, fig. 2 a, under view of mouth, the outer pairs of organs 

 removed — showing, e, the anterior margin of the buccal area — mx, the 

 summit of the inner branch of the first maxillipeds — md, the man- 

 dibles without the mandibular palpi ; b, one of the outer maxillipeds. 



Rio Janeiro, Brazil. 



Length of carapax, one inch seven and a half lines ; breadth be- 

 tween tips of long lateral spines, three inches and six lines; ratio of 

 length to this breadth, 1:2-15; breadth between the teeth next an- 

 terior, two inches ten and one-fourth lines ; ratio of length to this 

 breadth, 1:1-76. 



The habits of this species are different somewhat from the true 

 Lupas, the individuals being found along the sandy beaches, about 

 the harbour of Rio, — a peculiarity to which the name of the genus 

 alludes. The colour of the carapax, to which the specific name refers, 

 has a reticulated arrangement, there being a fine network of a pur- 

 plish slate-colour on a pale yellowish ground; on the arm and hand 

 the areolation is larger. The two teeth of the front either side of the 

 middle are smaller and are united so as to form a doubly- pointed 

 tooth, the inner point a little the longer. The arm is rather short, 

 and has three spines on its anterior margin. 



Portunus cribrarius, Lamarck, v. 259. 

 Lupa crihraria, Edwards, i. 452. 



Family V. PLATYOXYCIIID^E. 



Palatum lined elevatd utrinque non mhdivhum. Humus maxiWpedis 

 lmi interims simplex. Carapax angustus. Abdomen maris basi 

 angustum. 



