116 Bulletin Vanderhilt Marine Museum, Vol. V 



Xantho (Leptodius) crassimanus Alcock, Journ. Asiatic Soc. Bengal, 

 vol. 67, pt. 2, p. 120, 1898. 



Leptodius sanguineus (H. Milne Edwards). 



Plates 60 and 61. 



Type: Tlie type was collected in Mauritius and is deposited in 

 tlie Paris Museum. 



Distribution: Red Sea, (Ortmann) ; Payta; Halmahera, (Cano) ; 

 Indian Ocean, (A. M. Edwards) ; Persian Gulf, Andamans, Nicobars, 

 Laccadives, Ceylon, (Alcock) ; shore, Goifurfehendu Atoll, Maldives, 

 (Borradaile) ; Cocos Keeling Atoll, (Caiman) ; Rikitea (Nobili) ; Koh 

 Kahdat and Koli Chang, Gulf of Siam, (Rathbun) ; Ternate, (Cano) ; 

 Society Islands, Gilbert Islands, Paumotu Islands, Marquesas Islands, 

 (Rathbun) ; Marquesas Archipelago, (Boone) ; Sandwich Islands, 

 (Randall) ; Hawaiian Islands: Honolulu, reef; Waialua, Oahu, Hilo, 

 Puako Bay; Kealak Bay; Napili Harbor; Maui; Necker Island; 

 Waikiki Beach; Waianae; Kailua, (Rathbun); Marcus Island, 

 (Bryan) ; Palmyra and Fanning Island, (Edmondson) ; Upolu, 

 Samoa, Savii, (Pesta) ; Seas of the Isles of France, (H. M. Edwards) ; 

 Mauritius: Grand Port and Port Louis, (Bouvier) ; Peros, Coin, Salo- 

 mon, Praslin, Seychelles, Coetivy, (Rathbun) ; Zanzibar, Kokotoni and 

 Bawi, East Africa, (Lenz) ; Falcon Island, Palm Islands, Queens- 

 land, (Boone). 



Material examined: Thirteen specimens (including specimens 

 from one-half inch to one and one-half inches long diameter), from 

 coral at Falcon, Palm Islands, Queensland, October 7, 1931. Eleven 

 specimens of various sizes, collected on coral reef at Anaho Bay, Nuka 

 Hiva, Marquesas Isles, South Pacific, August 10, 1931. 



Technical description : The largest of the * * Alva ' ' specimens is a 

 male, having a long diameter of 35 mm., a length of 21.5 mm. 



The carapace is quite convex anteriorly and on the branchial lobes, 

 posteriorly less convex. The frontal margin is consistently narrower 

 than that of its near congener, Leptodius exaratus (H. Milne 

 Edwards), and consists of two submedian lobes, with truncated but 

 slightly concave margins, and separated from the inner orbital angle 

 by a distinct notch ; the median lobes being projected farther forward 

 than orbital tooth. Three closed sinuses occur and pucker the outer 

 half of the superior orbital margin. The external orbital angle is a 

 blunt tooth separated from the first anterolateral tooth by a wide con- 



