SOME WEST INDIAN ECHINOIDS. 5 



suggest that it is C. micans. In any case that species was dredged by the Blake as 

 is now stated by Clark. 



The genus Caloddaris, which was estabhshed by Clark for this species, is 

 evidently very nearly related to Cidans in the restrictetl sense (formerly Doro- 

 cidans). The characters pointed out by Clark are "the very broad and nearly bare 

 median ambulacral areas, the remarkable color, and the smooth, polished prima- 

 ries." As shown here the ambulacra do not really differ from those of Cidans. 

 There thus remain only the color and the character of the radioles. This is cer- 

 tainly not of much importance for a generic distinction — especially since Doctor 

 Clark does not otherwise consider the characters afforded bv tiie radioles as being 

 at all of generic value, as is so conspicuously shown by his conception of the genus 

 Phyllacanthus. Nevertheless, I think we can accept the genus, the radioles — in my 

 opinion — affording characters of sufhciently high value for generic distinction. 

 Compare my remarks on this matter in Die Echinoiden der deutschen Stidpolar 

 Expedition (p. 49). (In C. ahyssicola the radioles also appear very smooth; a 

 close examination, however, shows them to be finely striate and serrate — they 

 are not "polished" as in Calocidaris.) Also the whole appearance of this cidarid 

 is very characteristic. It thus seems to me that the genus Calocidaris may be valid; 

 but it seems likewise beyond question that it is closely related to the genus Cidaris 

 {Dorocidaris) . 



TRETOCIDARIS BARTLETTI (A. Agassiz). 



Plates 2-3; plate 7, fig. 6; plate 14, figs. 8-9; plate 15, figs. 8, 12-14; plate 16, figs. 2, 12; plate 17 



figs. 1, 6. 

 Doroddaris bartletti A. Agassiz, Bull. Mus. Comp. Zool., vol. 8, 1880, p. 69; Mem. Mus. 



Comp. Zool., vol. 10, 1883, p. 9, pi. 2, figs. 17-27, (not fig. 16).— R. Rathbun, Proc. U. S. 



Nat. Mus., vol. 8, 1885, p. 610; vol. 9, 1886, p. 261.— A. Agassiz and H. L. Clakk, 



Mem. Mus. Comp. Zool., vol. 34, 1907, no. 1, p. 8, pi. 12 a, figs. 6-13. 

 Tretocidaris bartletti Th. Mortensen, Ingolf Echinoidea, pt. 1, 1903, p. 16, pi. x, figs. 23, 



30; pt. 2, 1907, p. 169.— H. L. Clark, Bull. .\Ius. Comp. Zool., vol. 51, 1907, p. 203, pis. 



8-9. — Th. Mortensen, Echinoiden der deutschen Sudpolar Expedition, 1909, Ergbn.d. 



deutsch. Sudpolar Exped., XI, Zoologie, vol. 3, p. 47. 

 Tretocidaris annulala Th. Mortensen, Ingolf Echinoidea, pt. 1, 1903, p. 16, pi. 9, fig. 4; 



pi. 10, figs. 22, 31; pt. 2, 1907, pp. 169-170. 



This species, though it was not described before 1880, has had already a 

 rather intricate history, and it has played a somewhat prominent part in the dis- 

 cussion of the classification of the cidarids in recent years. The history is as follows: 



Having at first probably been confounded with Cidans ahyssicola as suggested 

 by Mr. Agassiz in the Preliminary Report on the Blake Echini it was established 

 as a separate species of the genus Doroddaris by him in the same paper. In the 

 final report on the Blalce Echini it was again described and figures were given 

 of the spines and of parts of the test; but unfortunately this description is insuf- 

 ficient and apparently the figures given are not all of this species. In the Ingolf 

 Echinoidea (pt. 1) , I established a new species, annulata, based upon an old specimen 

 seen in the British Museum. This supposed new species differed from bartletti mainly 

 in the structure of its test, the ambulacra having only a small secondary tubercle 

 on each plate inside the primary tubercle, whereas figure 16, on the second plate of the 

 Blake Echini shows the whole ambulacral area closely covered with secondary 



