CARCINOLOGICAL STUDIES. 89 



These two individuals have the following dimensions: 



cT 9 

 Greatest width of the cephalothorax . . 42 mm. 2572 mm. 

 Distance between the external orbital angles 34 » 22 V3 » 

 Breadth of the front, anteriorly . . . 21 » 13^/^ » 

 Length of the cephalothorax .... 35 » 22 » 



The cephalothorax of the (smaller) female specimen ap- 

 pears a little less enlarged than that of the male. 



Like Kingsley, I presume Leptograpsiis gonagrus }!. Milne 

 Edw., of which the habitat is unknown, to be identical 

 with this species. Pacliygrapsus maurus Lucas represents 

 our species in the Mediterranean Sea and seems to differ 

 by the front, which is slightly emai'ginate in the middle 

 and the external angles of which are not dentiform. 



Pacliygrapsus crassipes Randall inhabits California and 

 the Sandwich Islands. 



23. Plagusia speciosa Dana. 



Plagusia speciosa, Dana, 1. c. p. 369, PI. XXIII, fig. 9. 



One male from Paumotu and an ova-bearing female of 

 which the locality is unknown. 



As has already been observed by Miers (Report on the 

 Brachyura of the Challenger Expedition, 1886, p. 273, 

 footnote) , this species differs in many points from Plag, 

 immaculata Lam. and from the closely allied Plag. de- 

 pressa Say. 



The cephalothorax of Plagusia speciosa is broader 

 anteriorly than the cephalothorax of Plag. immaculata, 

 the distance between the external orbital an- 

 gles being considerably larger in proportion 

 to the length of the carapace. The upper surface is 

 convex in the same degree ; the tubercles are also depressed , 

 but all are bordered anteriorly by a fringe of short stiff hairs , 

 as in Plag. tuberculata Lam. The lateral margins are armed , 

 behind the dentiform external orbital angles , with only 

 two teeth, those of Plag. immaculata and depressahoYf- 

 ever with three ; these teeth are , however, comparatively 



JNotes from the Lieydeu Miuseutxi, Vol. XII. 



