CLYPEASTEE LATISSIMUS. 41 
Clypeaster latissimus A. Ag. 
Laganum latissimum Hupe, 1856, Castel Voy. Am. Sud., p. 98 (non Lam.). 
Yucatan Bank, Lesser Antilles. Santa Cruz, 248 fathoms ; Dominica, 98 fathoms ; Montserrat, 
88 fathoms ; Lat, 18" 12' N., Long. 64°, 1952 fathoms ; Granada, 92 fathoms. 
PL XV. Figs. 3,4; PI. XV'. Figs. 3, 4. 
The Blake dredged a number of specimens of the flat Clypeastroids. 
With this additional material I have made a renewed comparison of the 
species I had been led to unite under the name of Clgpcaster sn/jdejn-essus in 
the Revision of the Echini. 1 am now inclined to recognize three West 
Indian species of the genus Clypeaster, all of which had been before de- 
scribed on what I presumed to be insufficient data, and from the great 
variations I had observed in the shallow-water C. sitbdepressiis of Florida I 
was induced, at the time of writing the Revision, to consider these so-called 
species as all belonging to the common Florida species. The remarkable 
constancy of certain characters, however, in the series I have collected, has 
led me to return to the old specific distinctions, and to recognize three 
well-marked specific types in the genus. 
The typical Clgptaster subdepressiis, with a large rosette, a thick rounded 
edge, and the test but slightly arched in the petaloid region, and with close, 
remarkably uniform tuberculation extending over the whole of the actinal 
surface of the test, close to the ambulacral furrows, w'hich disappear in the 
tuberculation near the edge of the test. On the abactinal side the whole 
surface is covered by a close tuberculation, smaller than that of the oral 
surface, and the tubercles are separated by a fine granulation. 
The second species, C. latissinms, is marked for its thin test, and for its 
small ambulacral rosette, which does not extend more than half-way from 
the apex to the edge of the test ; the whole abactinal surface is covered by a 
close pavement of minute miliary granulation, with the exception of a small 
part of both the ambulacral and interambulacral areas adjoining the apex, 
where we find a few large distant primary tubercles. On the actinal side the 
tuberculation is very striking ; primary tubercles similar to those of the apex 
extend around the edge of the test, as they pass towards the actinostome 
diminishing rapidly in size on the ambulacra towards the median part 
of the furrow, which is covered by fine miliary granulations. Along the 
edge of the furrow there are small primaries passing into larger primary 
