REPORT ON THE ECHINOIDEA. 47 



specimens the most prominent primary spines are cylindrical, slightly curved, some of 

 them more than twice the diameter of the test in length (PI. I. fig. 12), tapering so 

 little that at the extremity, which is probably broken or worn, they are nearly of the 

 same diameter as at base. These long spines recall the spines of Salenia hastigera, and 

 remind us among the fossil Cidaridse very strongly of the cylindrical spiny radioles of 

 some species of Rhabdocidaris. These largest radioles are smooth, covered irregularly by 

 sharp spines, equalling its diameter in length near the base of the radioles (PI. I. fig. 1 8). 

 These spines are large and few in number near the base, becoming more numerous and 

 smaller towards the extremity of the radiole. Near the ambitus the radioles are .shorter 

 and more slender ; the serrations, closely crowded, sometimes form an irregular fluting 

 (PI. I. fig. 19), or they resemble the long curved cylinclrical primary radioles. Immedi- 

 ately around the abactinal area the primary spines, while similar in structure at the base 

 to the more prominent spines, are remarkable for the immense dilatations of the tip 

 (PI. I. fig. 12), the points of which frequently ramify, forming a flattened cup equalling 

 in diameter one-third the diameter of the test (PI. I. figs. 15, 16). 



In Goniocidaris tubaria and Goniocidaris gemnioides we find similar cupuliform 

 spines near the abactinal region, but the spreading of the tip of the radioles is not 

 so great in proportion to the diameter of the test. The papUlae covering the abactinal 

 area are small, with the exception of a few immediately surrounding the anal open- 

 ing (PI. I. fig. 12o); those at the base of the primary spines in the interambulacral 

 areas are short and broad, in striking contrast to the remarkably slender and delicate 

 papillae of the ambulacral area. There is a marked contrast in the curve of the actinal 

 and abactinal portions of the test ; the former is much more convex than is usual 

 among Cidaridae, the outline of the test when seen in profile resembling somewhat 

 the shape of the test of Echinostrephus. In another specimen (PI. I. fig. 7) there 

 are on the actinal side only a few of the cylindrical spines such as were characteristic 

 of the first specimen (PI. I. fig. 12), the other primary interambulacral radioles being 

 very uniform in character, slightly swollen above the coUar, gradually tapering to 

 a point, with large spines scattered over the whole surface of the shaft (PI. I. 

 figs. 8, 9), There are no cupuliform spines near the abactinal system. The radioles are 

 somewhat longer than the diameter of the test. The ornamentation of the test is limited 

 in this species to small deep pits at the angles of the plates in the median interambulacral 

 lines (PI. I. figs. 13, 14). The greater part of the coronal vertical sutures are edged by 

 irregular minute ridges, showing in the interval left between them the deep narrow sutural 

 line near the ambitus. Near the abactinal pole the vertical suture is reduced to a sharp 

 line. The secondary tubercles of the scrobicular area are in contact along the horizontal 

 lines of sutures (PL I. figs. 13, 14). Coronal plates high, mammary boss small, scrobi- 

 cular area deep. 



Along the horizontal suture, at the junction of the coronal plates with the poriferous 



