Boone, Crustacea, Cruise of "Alva," 1931 119 



Genus : ETISUS H. Milne Edwards. 

 Etisus dentatus (Herbst). 



Plates 62 and 63. 



Type: Type locality unknown to Herbst; depository the Berlin 

 Museum. 



Description: Indian Archipelago, (H. M. Edwards) ; Andamans: 

 Port Blair, Great Coco Island and East Island, (Alcock) ; Balabac 

 Passage north of Borneo, also Feejee Archipelago, (Dana) ; Tahiti, So- 

 ciety Islands, (Boone) ; Torres Straits, (Miers) ; Hawaii: Oahu, (Rath- 

 bun) ; New Caledonia and Mauritius, (Miers) ; Port Louis, Mauritius, 

 (Bouvier) ; Madagascar, (Lenz) ; Coetivy (Rathbun) ; Natal, South 

 Africa, (Stebbing). 



Material examined: One large male, collected by the "Alva," at 

 Papeete, Tahiti, Society Islands, August 15, 1931. 



Color: The carapace and legs are vivid scarlet, except that the 

 fingers of the chelipeds are ebony tipped with creamy white; hairs 

 of the legs golden. 



Technical description: Carapace 140 mm. wide, 90 mm. long; 

 frontal margin lamellar, with the frontal margin very slightly and 

 angularly excavate; divided in the median line by a distinct linear 

 groove which extends back on the gastric region. In some specimens 

 this groove is not entirely closed, having a narrow, elliptical, button- 

 hole like sinus, but this is obviously an individual variation. The 

 inner orbital angle is well separated from the frontal margin and is 

 bluntly angulated. The orbital margin has three strong conical teeth, 

 separated by sinuses, on this outer half and the inferior orbital tooth, 

 which is slightly stronger completes the orbital margin. The antero- 

 lateral margin is widely rounded and is produced into seven or eight 

 strong, acute, forward-curved teeth, in addition to the orbital tooth. 

 The teeth are strong but are uneven and unequal as to size some of 

 them, usually the third and fourth of the series are unequally bifid, 

 or even trifid, as shown in the plate. The dorsal surface of the cara- 

 pace is smooth but pitted with many coarse punctae and has the 

 regions well defined. The gastric region is circumscribed, its sepa- 

 ration from the cardiac region being weakly indicated, the hepatic and 

 branchial regions are also defined and all three regions have their sur- 

 faces uneven but not clearly lobulated. The sidewalls of the carapace 

 are smooth and the region of the carapace adjacent to the proximal 

 joints of the legs bears a heavy fringe of setae. The male belt is com- 



