2 I I 



As to the abdomen, it has been repeatedly stated in the present paper, that both in Ceratoplax 

 and in Typhlocarcinus the first segment in both sexes shows a tendency to extend laterally; 

 this has only been accomplished more fully in Typhlocarcinops and occurs also in my specimens 

 of Typhlocarcinodes. 



Five species of Typhlocarcinops have now been described by Miss Rathbun ^). The 

 "Siboga" collected one of these and, besides, two new species. 



Key to the species: 



1. Fronto-orbital width about equal to, or more than, half the 



greatest width of the carapace 2 



Fronto-orbital with much less than half the greatest width of the 

 carapace 6 



2. Postero-lateral margins of carapace parallel or divergent backward 3 

 Posterolateral margins of carapace convergent backward ; antero- 

 lateral margins with three groups of denticles or with blunt teeth 5 



3. Whole animal sparingly hairy. Eye-stalks almost circular; eye 



faintly pigmented; orbits somewhat sloping backward. Front 

 widening anteriorly. Antero-external angle of merus of external 



maxillipeds not produced T. canaliculata Rathbun -) 



Animal densely fringed. Eye-stalks piriform. Front not widening 

 distally 4 



4. Dactyli of walking legs regularly decreasing in length from the 



first to the fourth pair; propodites Shortened. Eyes faintly 



pigmented or quite pale T. decrescens Rathbun 



Dactyli of penultimate pair of legs distinctly exceeding in length 

 those of preceding and of following pair; propodites elongate, 

 narrowing distally. Eyes distinct, black, terminal T. angttstipes n. sp. 



5. Antero-lateral margins of carapace long, denticulate, "three inter- 



ruptions in the denticles forming three teeth" ; surface of 

 carapace rather well sculptured; breadth about 1.3 times its 



length. Eyes pigmented, dark T. marginata Rathbun ^) 



Antero-lateral margins of carapace shorter than postero-lateral 

 ones, very obtuse, with three blunt tubercles, widely separated ; 

 at the level of the posterior tubercles the carapace attains its 

 greatest breadth, which is about i^, times its length. Eyes 

 faintly pigmented T. transversa n. sp. 



i) A sixth species ( Z'. pirocnlaia) in reality belongs to Typhhcarchiodes. 



2) Proc. Biol. Soc. Washington, v. 22, 1909, p. 112; K. Dansk. Vid. Selsk. Skr,, 7. Raekke, Afd. 5, n" 4, 1910, p. 345, pi. 12, 

 f. 16, textfig. 32. Hab. Gulf of Siam. 



3) Proc. U. S. Nat. Mus., v. 48, 1914, p. 152. Hab. Philippines, 27 fathoms. The author remarks in the course of the diagnosis: 

 "this species is the only one of the genus in which the postero-lateral margins converge towards the posterior margin", but on the very 

 page two species are described, in which the same character is observed, and in one of these (?". angustifrons) it is even more pronounced 

 than in T. nmrgiitata. 



63 



