Dr. W. T. Caiman 07i Munidopsis polymorplia. 215 



to determine. Milne-Edwards and Bonvier *, in their arran (^e- 

 ment of the " Galatheeus non flagelles," attach primary 

 importance to the shape of the antero-lateral angle of the 

 carapace. Tliis angle is stated to be spiniform in the genera 

 Galacantha, Alunidopsi.t, and Galathodes, while it is " obtus, 

 ou formant un lobe saillant, parfois aigu," in Elasmonotus and 

 Orophorhynchus, Later writers are in agreement that the 

 division of genera is here carried too far, and Faxon f, 

 Alcock|, and Benedict § recognize only the two genera 

 Oalacantha and Munidopsis, the latter including Galathodes, 

 ElasmonotuSj and Orophorhynchus^ which by Alcock are 

 ranked as subgenera. The great variation in the shape of 

 the antero-lateral angles in the present species seems to 

 support this view, since they are sometimes spiniform as in 

 Munidopsis (s. str.), sometimes rounded as in Elasmonotus 

 and Orophorhynchus. Apart from this character and the 

 occasional absence of the rostrum, however, the species 

 appears to find its most natural place among the forms 

 composing the subgenus j]Iicnidopds, with which it agrees in 

 having the rostrum (when it is present) styliform in shape, 

 the chelipeds of the male longer than the ambulatory legs, 

 the eye-stalks not prolonged into spines, and the lateral 

 borders of the carapace not subcristiform. From all the 

 species of this group it is distinguished by, among other 

 characters, the great reduction of the rostrum, which, at 

 most, does not exceed twice the length of the eye-stalks. 



Of the 102 species of Munidopsis (s. lat.) enumerated by 

 Dr. Benedict, 21 are recorded from depths less than 

 300 fathoms, and of these only 2 are found in less than 

 100 fathoms, viz. M. Tan?ien\ Faxon, from 85 fath. in the 

 Gulf of Panama, and M. polita (S. I. Smith), from 79 fath. 

 off N.E. America 11. 



As in all the other species of the genus, the eyes of 

 M. polymorplia are very small and entirely without pigment 

 and the cornea is not facetted externally. The eye-stalks 

 are short, obtusely conical, and rounded at the apex ; they 

 are very slightly movable. In these characters and in the 

 small number and large size of its e.ggs M. polymorplia 



* " Oousideratious gen^rales sur la famille cles Galatheides," Ann. Sci. 

 Nat. (8) xvi. p. 260 (1894). 



t Mem. Mus. Comp. Zool. Harvard, xviii. pp. 81-83 (1895), 



\ Cat. Indian Deep-Sea Crust. Macrura and Anomala, p. 248 (1901). 



§ Proc. U.S. Nat. Mus. xxvi. p. 244 (1902). 



II Munidopsis tridentata (Esmark), which occui's in the deeper parts of 

 the Norwegian fjords, may perhaps extend into depths of less than 

 100 fathoms; but I cannot tind any definite statement on the subject. 



15* 



