THE SPIDEK CRABS OF AMERICA 



549 



Diagnosis . — Carapaca 

 one-third broader than long. 

 Branchial ridge strongly 

 curved. Branchial spine 

 the most slender. Movable 

 finger oblique, with a large, 

 smooth bead tubercle on 

 outside of base. 



Description. — Surface 

 minutely pubescent. Car- 

 diac, gastric, and branchial 

 elevations angular, each 

 prolonged in a three-sided 

 spine, the branchial spine 

 smallest and situated on 

 postero-lateral margin; an- 

 gles or ridges crenulate or 

 tuberculate; two ridges 

 gradually diverge from gas- 

 tric spine and are continued 

 nearly to front ; cardiac spine 

 longest, laterally com- 

 pressed; branchial ridge 

 curved, subparallel to an- 

 tero-lateral margin, and 

 having a larger tubercle at 

 the center; in front of 

 branchial ridge a few scat- 

 tered tubercles ; one or two 

 tubercles on hepatic region. 

 Surface concave behind 

 branchial ridge. Rostrum 

 short, pubescent. Antero- 

 lateral margin convex, dis- 

 tinctly crenulate; postero- 

 lateral and posterior mar- 

 gins entire, thin, faint im- 

 pressed lines indicating 

 normal crenulation ; postero- 

 lateral margin concave, 

 about twice as long as pos- 

 terior margin, which is 

 slightly convex in the mid- 

 dle and terminates in a 

 triangular flattened spine 



