CARCINOLOGICAL STUDIES. 57 



broader than long, its upper surface is very slightly convex 

 trausversely as well as in the antero-posterior direction , 

 especially in the female. The regions are tolerably well 

 indicated and defined by distinct, though shallow grooves. 

 The upper surface is minutely granulated anteriorly and 

 on the mesobranchial regions , for the rest smooth and 

 somewhat finely punctate. The front is strongly deflexed , 

 and the anterior margin appears nearly straight; the 

 epibranchial (or internal post-frontal) lobes are separated 

 from one another by the rather deep median furrow , which 

 is bifurcated as usual. The hepatic region is somewhat 

 concave. The orbits are large. The antero-lateral margins , 

 which in the other species of this genus appear more or 

 less convex, are, on the contrary, slightly concave 

 in Heterogr. spinosus ; they are armed moreover 

 behind the acute and prominent external orbi- 

 tal angle with three subequal, somewhat spi- 

 niform and comparatively small teeth; the 

 first tooth, formed by the external orbital 

 angle, is as long as the three posterior teeth 

 together. The cephalothorax has therefore its greatest 

 breadth at the fourth antero-lateral teeth. The postero- 

 lateral margins are nearly straight and slightly converge 

 backwards. The external maxillipedes leave a small rhom- 

 boidal gape between them , about as wide as those of 

 Heterogr. sanguineus de Haan and several other species. 

 Kingsley in his » Analytical key to the genera of G rap- 

 si da e" (Proc. Acad. Nat. Scienc. of Philadelphia, 1880, 

 p. 188) divides the genera according to the presence or 

 absence of the rhomboidal gape between the external foot- 

 jaws , and refers the genus Heterograpsus to that section in 

 which the outer foot-jaws are not gaping. He is evidently 

 wrong in doing so , and it would perhaps have been better 

 to have made no use at all of this character. The external 

 foot-jaws of Heterogr. oregonensis Dana leave no hiatus 

 between them , and Dana , for that reason , brought this 

 species to another genus (Pseudograpsus) and referred those 



Notes from the Leyden IMiiseum, Vol. XIII. 



