MUSEUM OF COMPARATIVE ZOOLOGY. 267 



Agassizii Mich., identical with it. There is a second species also found on 

 the West Coast, which Verrill has described as E. occidentals, and which 

 is identical with Encope tetrapora Ac non Gmel. From a careful com- 

 parison of specimens of E. cyclopora, micropora, and perspectiva, there is 

 no doubt that these are only nominal species, all identical with Verrill's 

 E. occidentalis ; and as the name micropora seems to be the most appro- 

 priate, it would be the best name to retain. 

 Littoral to 1 1 fathoms. 



Encope emarginata Ac, Agass. Cat Rais. 



Syn. Encope Valenciennesii Ag., Agass. Cat. Rais. 

 " subclausa " " " 



" oblonga " " " 



" quinqueloba " " " 



" Giiesbaehii Beval., Acad, do Brux. 

 " emarginata Lutk., p. p. Bidrag. 

 Moulinsia cassidulina Ag., Agass. Cat. Rais. (young ! ) 

 " " Lutk., Bidrag. 



Dr. Liitken, in his discussion of Encope emarginata, has given fio-ures 

 of young Encope after the appearance of the posterior interambulacral 

 lunule. Younger specimens in our collection, before the appearance of 

 this posterior lunule, show that Moulinsia is only a young Encope emargi- 

 nata. As in my account of young Echini I have given a full description of 

 the changes Encope undergoes during its growth, I will only recall them 

 here to justify the synonymy adopted. 



Littoral to 7 fathoms. 



Echinoneus semilunaris Lam., An. s. v. 

 Syn. Echinoneus semilunaris Lutk., Bid. 



clegans A. Ag., Bull. M. C. Z., No 2. 



Liitken, like myself, has only been able to recognize one species in the 

 We • India Islands. As is well known, the difficulty of distinguishing the 

 species in this genus is very great ; the more so, as thus far only tests with- 

 out spines have been used in the determination .of species. Mr. Pourtales 

 has collected one specimen at Carysfort Reef with its spines and tentacles, 

 which gives us the first opportunity of making a direct comparison with 

 specimens from the Sandwich Islands (the true E. cyclostomus) still retain- 

 ing the anal and buccal membranes. As far as I am able to discriminate 

 between the test of these two species, the Pacific species is remarkable for 

 the narrowness of its poriferous zone, the pores being placed in close con- 

 tact, separated by a ridge carrying small tubercles, while in the specimens 



