CRUSTACEA. 
487 
TRIBE I.-QUADRILATERA. 
With the thorax nearly square, sometimes heart-shaped, ex¬ 
panding, and rounded at the anterior angles, and truncated 
at the posterior extremity; front advanced, with a greater or 
lesser inclination ; none of the feet terminated by a fin. 
This tribe contains ten genera, namely;—1. Ocypode; 2. Ge- 
lasimus ; 3. Myctris; 4. Pinnotheres; 5. Gecarcinus; 6. Pia- 
gusia; 7. Grapsus; 8. Gonoplax; 9. Thelphusa; 10. Eriphia. 
Genus 4.—PINNOTHERE S .—Latreille. 
Generic Character _With very short antennae, the three first 
joints the largest, inserted in the interior corner of the eyes; 
exterior feet-jaws curved, with the third joint large; forceps 
equal; shell thin, flexible, orbicular, or nearly square; eyes 
thick. 
Pinnotheres pisum. — The Pea Pinnotheres. 
Plate XCIII. tig. 4. 
Female with an orbicular shell, soft, and nearly square, en¬ 
tire, a little arcuated before; shell of the male contracted in 
front; hands oblong, with a line of hairs beneath. Inhabits the 
European coasts, in bivalve shells. 
Genus 8. — GONOPLAX.— Leach. 
Generic Character. —Exterior antennse setaceous and distinct, 
the three first joints thicker than the others; exterior feet-jaws 
approaching, the fourth joint inserted at the interior upper angle 
of the third, which is pentagonal and transverse ; the anterior 
pair of legs very long; forceps equal and elongated ; eyes on the 
termination of their peduncle. 
Gonoplax bispinosa. — The Two-Spined Gonoplax. 
Plate XCIII. fig. 5. 
Shell armed with two spines on each side; wrists and arms 
above with one internal spine. Inhabits the coast of England. 
TRIBE II.-ARCUATA. 
Shell anteriorly arcuated near the middle of the sides, nar¬ 
rowed, and posteriorly truncated. 
