56 



Genus Uroptychus, Henderson. 



Diptychus, Milne-Edwards, 1880. Diptychus, Bonnier^ 

 1888. Uroptychus, Henderson, 1888. Diptychus, Milne- 

 Edwards and Bouvier, 1894 (a). Uroptychus, Alcock, 1901. 

 Uroptychus, Stebbing, 1903. 



The two Irish species may be distinguished from one another 

 by the following characters : — 



Dorsal surface of carapace bearing numerous 

 fine hairs, especially on branchial and hepatic 

 areas ; no movable spines on lower edge of 

 propodite of walking legs ; upper and lower 

 surface of chelipeds covered with small scales, 

 which bear each a row of long hairs, . . U. rubrovittatus. 



Dorsal surface of carapace devoid of hairs, 

 very smooth and shining, minutely punctate ; 

 lower edge of propodite of walking legs bears 

 a row of movable spines ; chelipeds quite 

 smooth, without scales, and without hairs, 

 except at the tips of the fingers, 



U. nitidus, var. concolor. 



Uroptychus rubrovittatus (Milne-Edwards). 



PI. VIII, figs. 1-4. 



Diptychus rubrovittatus, Milne-Edwards, 1881. 

 Diptychus rubrovittatus. Bonnier, 1888. 

 Uroptychus rubrovittatus, Caullery, 1896. 

 Diptychus rt^&romffa/w5, Milne-Edwards and Bouvier, 



1900. 

 Uroptychus rubrovittatus, Hansen, 1908. 



The carapace is broadest in the branchial region ; it is slightly 

 narrower behind, and considerably so in front. The rostrum is 

 large and triangular, with very slightly crenulated margins ; 

 it is slightly hollowed out on the upper surface. The carapace 

 is arched from side to side, and is almost quite smooth ; the 

 cervical groove is represented by a faint crescent-shaped de- 

 pression. There is a sparse covering of tufts of fine hairs which 

 are most plentiful on the branchial and hepatic areas, and also 

 occur on the upper surface of the rostrum. The posterior margin 

 is slightly concave. The lateral margins have a row of very 

 small tubercles which do not come to sharp points. There is an 

 inward curved spine at each antero-lateral angle, and there is 

 a smaller spine on the anterior margin above the base of each 

 antenna. The linea anomurica is distinctly marked. The sub- 

 marginal parts of the carapace bear a number of small and rather 

 obscure tubercles, which, however, are absent from the central 

 part. 



