Boone, Crustacea, Cruise of "Alva," 1931 53 



Subfamily : Thalamitrinae. 

 Genus : charybdis DeHaan. 

 Chaxybdls crucifera (Fabricius). 



Plate 17. 



Type: This was secured in the East Indies and deposited in the 

 Berlin Museum. 



Distribution: East Indies, (Herbst) ; Indian Ocean, (Latreille, 

 H. M. Edwards, Paris Mus, coll.) ; Hong Kong, abundant in the reefs, 

 (Stimpson, Miers, N. G. Gee, Chen) ; Foochow, (Gee) ; Bombay, 

 Pondichery, (A. M. Edwards) ; Trincomali, Ceylon, (F. Muller) ; 

 Akyab, Tuticorin, not uncommon at Madras, (Henderson) ; Singa- 

 pore, (Dana, Walker, Cano; Ortmann: Nobili; Kemp); Trengganu, 

 Malay Peninsula, Lanchester) ; Gulf of Siam, (Rathbun) ; Sumatra, 

 Java, Philippines (A. M. Edwards) ; East Indies, (Dana) ; Amboina, 

 King Island, Mergui Archipelago, (de Man) ; Java Sea, (de Man) ; 

 Celebes, (Thallwitz) ; Makassar, Celebes, (Rathbun) ; Port Jackson, 

 Australia, (Haswell) ; Sydney, N. S. Wales, (McNeill) ; Port Alfred, 

 South Africa, (Stebbing). 



Material examined: Three large males and eight small crabs, 

 taken in large jellyfish, Muntok, Banka Island, Banka Straits, Dutch 

 East Indies, Nov. 5, 1931, by the "Alva." 



Technicali DESCRIPTION: Carapace oval, with the frontal and 

 anterolateral margins widely rounded, three-fourths as long as wide; 

 the dorsal surface is moderately convex, finely tomentose ; the regions 

 are poorly delineated ; one granular curved line runs inward from the 

 sixth or last postlateral tooth across the branchial region and converges 

 toward the urogastric depression. Anteriorly there are two trans- 

 verse broken lines across the mesogastric region. These lines are more 

 conspicuous in the young crabs, frequently being obsolete or nearly 

 so, on older specimens. The frontal border is about two-sevenths of 

 the total width of carapace and is cut into six conspicuous, subequal, 

 bluntly rounded teeth, in addition to the two smaller, preorbital teeth, 

 which are set apart from the others by a slightly wider gape. The 

 inner four frontal teeth are about equal, while the outer two are 

 slightly narrower ; the preorbital tooth is a blunt triangle directed for- 

 ward and upward, but does not extend as far forward as the frontal 

 teeth. The inferior inner orbital tooth is a broad triangle and is also 

 visible in the dorsal view, lying below and a little outside the superior 



