48 CONOLAMPAS SIGSBEI. 
Conolampas A. Ag. 
Conoclypus A. Ag. Bull. JI. C. Z., V., No. 9, p. 190, 1878 [non auct.]. 
* Conolampas Sigsbei A. Ag. 
Conoclypus Sigsbei A. Ag. Bull. M. C. Z., V., No. 9, p. 190, Pis. I, II., 1878. 
Yucatan Bank, off Havana, Lesser Antilles. 76-450 fathoms. 
For list of Stations, see Bull. M. C. Z., VIIL, 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 
hu2;e brilliant lemon-colored Echini. 
The test is covered by small primai-y tubercles of uniform size, quite regu- 
larly arranged on the plates of the test, both on the ambulacra! and inter- 
ambulacral 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 Echinolampas 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 Ehynchopygus ; but near the ambitus 
on the actinal side, where the primary tubercles are most closely crowded, 
they are 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 actinostome to the ambitus. 
There are small, elongate, short-stemmed, slender pyramidal pedicellaritB 
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 ai-e 
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 are four large genital openings ; 
the odd posterior genital is wanting. The ambulacral zones are all iden- 
tical in structure, two i-ows made up of distant pores extending two thirds 
