OXYSTOMATOUS AND ALLIED CRABS OF AMERICA 75 



Range. — Both sides of North Atlantic Ocean; Mediterranean Sea; 

 70 to 200 fathoms. Natal, 25 fathoms (Stebbing). 

 Material examined. — See table 21, p. 76. 



Subtribe Oxystomata De Haan 



Oxystomata De Haan, Fauna Japonica, Crustacea, p. Ill, 1841 (not Raninoi- 

 dea). — Dana, United States Exploring Expedition, Crustacea, pt. 1, p. 3S9, 

 1852. — MiEKS, Voyage of H. M. S. Challenger, Brachyura, vol. 17, p. 337, 

 1886.— Ortmann, Zool. Jahrb. (Abt. Syst.), vol. 6, p. 550, 1892. 



Oxystoma or Leucosoidea Alcock, Journ. Asiat. Soc. Bengal, vol. 65, pt. 2, 

 no. 2, p. 135, 1896. 



Epistome reduced or absent. The efferent branchial channels ter- 

 minate at middle of buccal area, the buccal cavern produced forward 

 and generally of an elongate triangular shape; the efferent channels 

 are closed in by an elongate lamellar process of the exopods of the 

 first maxilHpeds. The afferent branchial openings are either in front 

 of bases of chelipeds or at sides of endostome. Branchiae six to 

 nine on either side. The antennules fold either longitudinally or 

 obliquely, rarely transversely. In the male the genital ducts pro- 

 trude either side through the bases of the fifth pair of legs or through 

 the fifth thoracic sternum close by. (After Alcock.) 



KEY TO THE FAMILIES OF THE StTBTRIBE OXYSTOMATA 



A*. Carapace short, exposing the first two or three abdominal terga 



in dorsal view Dorippidae (p. 75) 



A^. Carapace of ordinary brachyurous shape. 



Bi. Afferent branchial openings on either side of endostome. 



Leucosiidae (p. 121) 

 B2. Afferent branchial openings in front of bases of chelipeds. 



Calappidae (p. 196) 



Family DORIPPIDAE Dana 



Dorippiens Milne Edwards, Histoire naturelle des Crustac(5s, vol. 2, p. 151 

 (partim), 1837. 



Dorippidea De Haan, Fauna Japonica, Crustacea, p. 120, 1841. 



Dorippidae Dana, United States Exploring Expedition, Crustacea, pt. 1, p. 390, 

 1852. — Miers, Voyage of H. M. S. Challenger, Brachyura, vol. 17, p. 326, 

 1886. — Alcock, Journ. Asiat. Soc. Bengal, vol. 65, p. 273, 1896. — Ihle, 

 Die Decapoda Brachyura der *Si6o5fa-Expedition, monogr. 39 b', p. 98, 1916. 



Carapace typically flat, hiding not much more than half of the 

 abdominal terga, the first three of which are commonly visible in a 

 dorsal view, quite uncovered. Orbits somewhat incomplete. Anten- 

 nules often too large to fold inside their fossettes. Antennae large. 

 Buccal cavern prolonged forward to form an efferent branchial 

 canal. First two pairs of true legs remarkably long and stout; last 

 two pairs remarkably short and slender and occupy a singular posi- 

 tion in the dorsal plane of the body. The vasa deferentia perforate 

 the fifth thoracic sternum on either side. 



80232—37 6 



