CLYPEASTER LATISSIMUS. 41 



Clypeaster latissimus A. Aa 



Iiaganum latissimum lln-i';. 1856, Caste] Voy. Am Sud., p 98 



Yuen B I Santa Cruz, 248 fathoms ; Dominica, 98 fathono 



88 fathoms ; Lat. I s 1-' N., Long. 64°, 1952 fathoms ; Granada, 92 fathoms. 



/'/. .VI"'. Figs. S, ',-. Pi. XV. Figs. S, 4. 



The Blake dredged a number of specimens of the flat Clypeastroids. 

 With this additional material 1 have made a renewed comparison of the 

 Bpecies 1 had been led to unite under the name of Clypeaster subdepn 

 tlic Revision of the Echini. I am now inclined to recognize three Wesl 

 Indian species of the genus Clypeaster, all of which had liccn before de- 

 scribed on what 1 presumed to be insufficient data, and from the great 

 variations I had observed in the shallow-water ('. subdepressus of Florida 1 

 was induced, al 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 1 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 Clypeaster subdepressus, with a large rosette, a thick rounded 

 edge, and the tesl bul 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 ambulacra] furrows, which disappear in the 

 tuberculation near the edge of the test. On the abactinal side the whole 



-nil. ice is covered by a close t ul lereulat ion. smaller than that of the oral 



surface, and the tubercles are separated by a fine granulation. 



The second Bpecies, C. latissimus, is marked for its thin test, and for it- 

 small ambulacral rosette, which does not extend more than half-way from 

 the apex to the edge of the test j the whole abactinal surface is covered by a 

 close pavemenl of minute miliary granulation, with the exception of a small 

 part of both the ambulacra] and interambulacral areas adjoining the apex, 

 where wc find a few large distanl primary tubercles. On the actinal side the 

 tuberculation is verj 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 pari 

 of the furrow, which is covered bj fine miliary granulations. Along the 

 edge of the furrow there are small primaries passing into larger primary 



