CLARK: THE CIDAPJDAE. 203 



fails to mention the pedicellariae. The test of tiara is chestnut-brown, green 

 abactinally, especially towards the anus; the secondaries are olive-greeu with a 

 darker longitudinal band. The largest specimen was 42 mm. h. d. The only 

 recorded locality for tiara is off Colombo, Ceylon, in 142-400 fths. 



Tretocidaris affinis. 



Cidaris affinis Philippi, 1845, Arch. Naturg., 11 Jhrg., 1, p. 351. 



Plate 1, fig. 5, Rev. Ech., A. Agassiz, 1872. Plate 1, fig. 1, Ingolf-Exp. Ech., 



Mortensen, 1903. 



This well-known species has been confused with Dorocidaris papillata so long 

 that it may be hard to believe it is really quite different. We are indebted to 

 Mortensen (:03) for showing its right to specific rank (although he makes no 

 reference to the abactinal system !), but we cannot follow him in placing it in the 

 genus Cidaris. Mediterranean and West Indian specimens appear to be alike in 

 all particulars ; Mortensen says the tridentate pedicellariae were wanting in his 

 Mediterranean specimens, but those in the collection of the M. C. Z. from Cape 

 Sagras and from the Mediterranean have them normally developed. Mortensen 

 says the spines are 1-1.5 h. d., but our large series of specimens show a much 

 greater range, 1.25-2.40 h. d. The largest specimen is 38 mm. h. d. The color 

 is variable, but the small spines of the test are more or less greenish, tipped with 

 dark red, while the entire abactinal system (or at least the sutural lines) and the 

 bare areas on ambulacra and interambulacra are dark red ; the primaries are dull 

 grayish, more or less pink or white near base, and with a greenish or brownish 

 collar. In West Indian specimens the color is often very light, the secondaries 

 and test being nearly cream-color with the former tipped with reddish. In other 

 West Indian specimens the color is sometimes nearly slate-color, with little trace 

 of reddish. This species ranges throughout the North Atlantic eastward into the 

 Mediterranean, and southwestward to Barbados and the Gulf of Mexico, down 

 to a depth of 500 fths. 



Tretocidaris bartletti- 



Dorocidaris Bartletti A. Agassiz, 1880, Bull. M. C. Z., 8, 2, p. 69. 

 Tretocidaris bartletti Mortensen, 1903, Ingolf-Exp. Ech., p. 16. 



Plates 8 and 9. Also Plate 3, figs. 16-27, Blake Ech., A. Agassiz, 1883. 



In his original description Agassiz called attention to the resemblance between 

 the. primary spines of this species and of Stephauocidaris. Young specimens of 

 bartletti, for this reason, show quite a striking resemblance to young specimens of 

 that genus, but a careful examination shows important differences in the primaries 

 as well as in the test. In spite of the very great diversity exhibited in both its 

 spines and its pedicellariae, there can be no question as to the real relationship of 

 this species. Mortensen (: 03) names two closely allied, supposedly new species, 

 whicii he found in the British Museum ; one, annulata, I am unable to distinguish 



