106 IOWA STUDIES IN NATURAL HISTORY 



one of the present series, these young spines are distinctly pink 

 and unhanded. Fully developed primaries are more than twice 

 the test-diameter, nearly cylindrical or terete, with the distinct, 

 dentate, longitudinal ridges equally developed on all sides. In 

 specimens less than half grown they are often conspicuously 

 banded with 5-8 ill-defined reddish-brown zones. 



The specimens in the present collection were taken at the fol- 

 lowing stations off the southwestern coast of Barbados. 



Station 9. May 16, 1918. W. by N. Pelican Island, 21/2 miles, 



100 fms. Rocky bottom. Tangles. 2 specimens. 

 Station 34. May 23, 1918. S. E. of Hastings, 2 miles off shore, 



80-90 fms. Rocky bottom. Tangles. 1 specimen. 

 Station 36. May 23, 1918. S. W. of Carlisle Bay, 2 miles off 

 shore, 80-90 fms. Rocky bottom. Tangles. 1 specimen. 

 Station 46. May 25, 1918. N. N. W. Pelican Island, due west 

 of Prospect, 2 miles off shore, 100 fms. Tangles. Bottom 

 not recorded. 1 specimen. 



TRETOCIDARIS BARTLETTI 



Dorocidm-is hartletti A. Agassiz, 1880. Bull. M. C. Z., 8, p. 69. 

 Tretocidaris hartletti Mortensen, 1903. Ingolp Ech,, p. 16. 1910, 



Bull. 74 U. S. Nat. Mus., pis. 2 and 3. 



As with the preceding cidarid, all of the half-dozen individuals 

 of this fine species are young, not nearly half grown, the test 

 diameter ranging from 10 to 17 mm., with the primary spines 

 15-27 mm. The color is commonly brighter than in affinis, the 

 reddish tints being usually quite red and the test and small 

 spines being often quite greenish. The bands on the spines are 

 generally distinct and their number may be 8 or 9, although the 

 spines are shorter than in affinis. The two species seem to occur 

 together and the young are easily confused. But aside from any 

 matters of coloration, the form of the primary spines is sufficient 

 for separating the two species, even if the very different glob- 

 iferous pedicellariae cannot be found. In hartletti, the typical 

 primaries are flattened and the lateral dentate ridges are more 

 conspicuous, with bigger dentations, than those of either dorsal 

 or lower surface. This makes a noticeable contrast to the cylin- 

 drical, uniformly ridged and generally longer spines of affinis. 



