48 CONOLAMPAS SIGSBEI. 



Conolampas A. Ac. 



Conoclypus A. Ag. Bull. M. C. Z., V., No. 9, p. 190, 1S78 [non auct.]. 



* Conolampas Sigsbei A. Ag. 



Conoclypus Sigsbei A. As. Bull. M. C. Z., V., Xo. 9, p. 190, Pis. I., II., 1878. 

 Yucatan Bank, off Havana, Lesser Antilles. 7ti-40<) fathoms. 

 For list of Stations, sue Bull. M. C. Z., VIII., No. 2, p. 80, 1880. 



PI XVII. 



This magnificent species is by far the most striking Sea-urchin I have 

 seen. I shall always remember the particular haul, when, on the edge of 

 the Yucatan Bank, the dredge came up containing half a dozen of these 

 huge brilliant lemon-colored Echini. 



The test is covered by small primary tubercles of uniform size, quite regu- 

 larly arranged on the plates of the test, both on the ambulacral and inter- 

 ambulaeral areas. The tubercles on the actinal side are similarly arranged, 

 with the exception of the vicinity of the ambitus, where they are more 

 closely crowded together. The primary tubercles are surrounded by a deeply 

 sunken scrobicular area, much as in Echinolainpas and Rhynchopygus. The 

 miliary tubercles are uniformly scattered between the primaries, and are 

 separated by irregular transparent glassy ridges and elongated pits, much 

 as we find them on the actinal side of Rhynchopygus; but near the ambitus 

 on the actinal side, where the primary tubercles are most closely crowded. 

 they arc separated by closely packed secondary tubercles. The actinal 

 bourrelets are very prominent ; the floscelle is large, broad, well defined, ex- 

 tending nearly one third the distance from the actinostoine to the ambitus. 

 There arc small, elongate, short-stemmed, slender pyramidal pedicellariae 

 scattered irregularly over the actinal surface; they are much less numerous 

 on the sides of the test. The primary spines are short, slender, cylindrical, 

 rapidly tapering at the extremity; the miliary and secondary spines are 

 similar to the primary ones, but smaller. The apical system is compact, 

 the genital plates all coalesce, the centre of the apex is occupied by the 

 madreporic body, which is developed into a prominent knob, on the sides 

 of which the ocular plates rise. There tire four large genital openings ; 

 the odd posterior genital is wanting. The ambulacral /ones are all iden- 

 tical in structure, two rows made up of distant pores extending two thirds 



