CCELOPLEURUS. 83 



curviitui-e of the primaries is not so marked in small specimens as in the 

 large ones, and the peculiarity of elegans in these particulars may be due, in 

 part at least, to the small size of the specimen, which is only about 10 mm. 

 h. d. Aside from the obvious differences in color, the species are dia- 

 tino-uished from each other by the characters of the collar on fully devel- 

 oped primaries and the form of the valves of the ophicephalous pedicellariae. 

 The following table will make these differences clear, it being understood 

 that only unbroken, fully developed spines from the interambulacra, at or 

 near the ambitus, of mature specimens, are meant, when " primaries " are 

 referred to ; when " length " of valve is mentioned in connection with 

 pedicellariae, it is understood that the "articular loop" is not included 

 in the measurement. 



Primaries spotted or banded, at least on basal half ; collar less than ten per 

 cent of length of spine. 



Markings on primaries distinctly purple ; ground color green ; collar about 

 eight per cent of spine-length, finely granular, without conspicuous lon- 

 gitudinal ridges but with distal margin oblique ; valves of ophicephalous 

 pedicellarife decidedly constricted, the least width of blade not more 



than .40 of length of valve Maillardi. 



Markings on primaries bright red; collar about five per cent of spine- 

 length. 



Ground color of primaries bright green ; collar rough with 12-15 con- 

 spicuous longitudinal ridges and with distal margin horizontal ; 

 valves of ophicephalous pedicellariae not greatly constricted, the 



least width exceeding .60 of length maculatus. 



Ground color of primaries bright yellow ; character of collar and 



pedicellariae unknown elegans. 



Primaries not spotted or banded except occasionally on distal half ; collar more 

 than ten, often more than twenty per cent of spine-length, rough with finely 

 serrate longitudinal ridges. 



Primaries more or less uniformly red, at least on abactinal surface ; collar 

 extends distinctly farther on abactinal ridge than on sides of spine ; 

 valves of ophicephalous pedicellariae decidedly constricted, the least 



width not exceeding .50 of length floridanus. 



Primaries more or less uniformly whitish, sometimes with spots of red 

 distally ; collar does not extend distinctly farther on abactinal ridge 

 than on sides of spine ; valves of ophicephalous pedicellariae not con- 

 stricted, the least width exceeding .70 of length longicolUs. 



