Dr. W. T. Caiman on .Munidopsis polymorpha. 21.') 



to determine. Milne-Edward.-? and Bouvifi*, in their arrann;e- 

 ment of" the " Galath^ens non fla^^eiles," attacli primary 

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

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

 Galacantha, Mimidop.n'i, and Galathodes, while it i.s " obtus, 

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

 Oropkorhynchus. Later writers are in agreement that the 

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

 Alcock J, and J3enedict§ recognize only the two genera 

 OaJacantha and Munidopsis, the hitter including Galathodes, 

 ElasmonotuSf 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 tliis view, since they are sometimes spiniform as in 

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

 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 Munidopsis, 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. Tanueri, Faxon, from 85 fath. in the 

 Gulf of Panama, and M. polita (S. I. Smith), from 71) fath. 

 oft N.E. American. 



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

 ^[. polymorpha are very small and entirely without pigment 

 and the curnea 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 eggs M. polymorpha 



* " Considerations g^n^rales sur la famille des Galatheid^s," Ann. Sci. 

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



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



j Cat. Indian Deep-Sea Crust. Macnira and Anomala, p. 248 (1001). 



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



II Munidopsis tridentata (Esuiaik), which occurs in the deeper piirts of 

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

 100 fathoms; but I cannot tiud any definite statement ou the subject. 



15* 



