62 
ON THE BRACHYUROUS DECAPODS OF THE CAPE. 
equal, the tooth nearest the eye being sharp. So are the teeth of the clypeus, and the four 
middle of these teeth are scarcely separated from the lateral ones by a deeper incision. The 
fore-feet are equal in size, having two apical teeth on the upper margin of the fourth joint. The 
length is about two inches. The abdomen of the female has six joints. 
Fam. CARCINIDiE, Leach. 
Sub-genus. Anisopus, Dehaan. 
Sp. 14. ( ) Anisopus trimaculatus, Dehaan. 
Anisopus 3-maculatus, Faun. Jap. p. 13. 
Platyonychus Mpustulatus, M. E. Hist. Nat. des Crust, vol. i. p. 437. tab. 17- 
fig. 7. 10. 
Note. This crab has a strong relation to the Corystidce, which Professor Dehaan has pointed 
out with his usual acumen. By Anisopus, in fact, we pass off to the Corystina among the 
Trigonostomous Brachyura. 
Sub-genus. Xaiva, M‘L. 
Cephalothorax rather depressed, as broad as long, but narrower behind, being broadest in the 
middle, and having the sides in front arched with a five-toothed margin ; the tooth behind 
the eyes being broad and truncated. The sides behind are entire, rather concave, and 
with a margin. The shell behind is also entire and margined. The clypeus is triangular, 
advanced with an acute point, and having the sides undated, while it is furnished above 
on each side at its base with an orbital tooth. 
Orbit with two teeth below, the outer one of which is triangular, and larger than the other. 
External antenna; inserted within the orbit, and having their basilar joint short and sub- 
triangular. 
External pedipalpi, with the second joint, almost twice as long as the third, which is sub- 
quadrate, carinated at the base, with the point obliquely truncated, acuminated on the 
outside ; the inner margin having a piece cut out, as it were, above its middle. 
Feet, first pair with the chelae bicarinated above ; second, third, and fourth pair with slender 
nails, while the hind pair has the nails or ungues dilated and pointed as in the genus 
Carcinus. 
Abdomen of male has seven segments ; but the third, fourth, and fifth appear soldered together. 
Xaiva is the Spanish name for all crabs which have the posterior feet natatory. This will 
be seen on referring to the curious work of Parra on the natural history of the Gulf of Mexico. 
The present sub-genus comes close to Carcinus of Leach ; but is easily distinguished by 
the third joint of the external pedipalpi. 
Sp. 15. ( ) Xaiva pulchella, n. s. 
Descr. Xairn testa margine anteriore subreflexo, tuberculis quatuor in regione stomachal!, linea 
utrinque elevata in tuberculum lateralem dcsinente, chelis supra bicarinatis et extus 
tricarinatis. 
Note. The stomachal region in this pretty little crab is marked by four tubercles, which are 
situated on an elevated ridge, stretching on each side towards a lateral tubercle, which is almost 
on the middle tooth of the anterior lateral margin of the shell, ihe genital region is maiked by 
