20 PANAMIC DEEP SEA ECHINI. 



GONIOCIDARID-ffi Haeokel. 



Dorocidaris A. Ag. 



Dorocidaris panamensis A. Ag. 



Dorocidaris panamensis A. Ag., Bull. M. C. Z. XXXII, No. . r >. p. 73, Plates I ; II, fig. 1, 1898. 



Plates 1-4. 



This is the Pacific representative of D. -papillata, from which it is distin- 

 guished by its pentagonal anal system, the flattened test, the closer granu- 

 lation of the plates of the apical system, while the secondary tuberculation 

 of D. panamensis is closer than that of D. papillata. In the largest specimen 

 examined, measuring 36 mm. in diameter, the primary radioles attained 

 a length of only 50 mm. (PI. 1, figs. /, 2), and in many specimens the 

 radioles were not longer than the diameter of the test. The radioles are 

 more slender than those of D. papillata, and their granulation coarser 

 (PI. 4, figs. 9, 12), resembling as a whole more those of Goniocidaris cana- 

 Kculata. The test of this species is depressed (PL 2, figs. 3, 4); the 

 miliary spines are reddish-brown, giving the test when alive a general 

 chestnut coloring. The shorter primary radioles of the actinal side are 

 marked for their proportionally slender shaft (Pis. 1, figs. ..', 4; 2, fig. ..'); 

 they are fairly smooth, delicately striated. The coronal primary radioles 

 vary greatly in ornamentation, from a delicate striation to a serration 

 formed of short blunt spines passing into a granular structure (PL 4, 

 figs. 0-11). 



In a specimen measuring 30 mm. in diameter, with seven primary inter- 

 ambulacral plates (PL 3, figs. 5, G), the actinal system is only 10 mm. in 

 diameter (Pis. 2, fig. 2; 3, fig. 4)- The abactinal system of the same 

 specimen measured 15 mm. in greatest diameter, with two rows of eleven 

 ambulacral buccal plates and two pairs of pores detached from the actinal 

 extremity of the ambulacra, and five interambulacral buccal plates in each 

 interradial space (PL 3, fig. •/). The secondary tubercles and miliaries are 

 crowded on the actinal side of the older buccal plates, (PL 3, fig. 4)- 

 The test as well as the actinal and abactinal systems are crowded with 

 short-headed, long-stemmed, tridentate pedicellariae. The secondary tuber- 

 cles and miliaries of the interambulacral areas (PL 3. fig. 6) are smaller 

 than those of D. papillata. In the ambulacral areas the outer row of 

 primary tubercles consists of larger and more prominent tubercles than 



