/. ' ( 
44 NEOLAMPAS EOSTELLATA. 
Encope Michelini Agass. 
Yucatan Bank. 14 fathoms. 
Echinoneus semilunaris Lamk. 
Cuba. Littoral to 80 fathoms. 
Neolampas rostellata A. Ag. 
Florida Bank. 229 fathoms. 
^^ PL XXII. 
A number of specimens of this interesting genus, of all stages of growth, 
having.been collected by the Blake in the Straits of Florida, I am able to 
add considerably to our previous knowledge of the genus. As in all Cas- 
siduloids, the affinities of the family to the Clypeastroids is more or less 
marked. In the young specimens from Florida the changes taking place 
in the actinostome, in the anibulacral system, and in the shape of the test, 
as well as the structure of the pedicellarise and of the abactinal system, all 
show strikingly the close affinities of the family with the Clypeastroids. 
In the youngest stage examined, measuring only 2.5 mm. in length, the 
test, instead of being globular, as is the case in the Spatangoids proper, is 
quite flattened, its outline is elliptical, the anal system is covered by few 
large plates, and the general aspect of the young Neolamjjas at this stage 
and in the following one, when it measures about 4.5 mm. in length, closely 
resembles the young of some of the true Clypeastroids which I have had 
occasion to examine, such as Echlnocyamus, Mellita, or Echinarachnius. 
On their first appearance the bourrelets and phyllodes are with difficulty 
made out, and in the earliest stages the actinostome shows no trace what- 
ever of them. The anibulacral suckers are, like those of the Clypeastroids, 
provided with powerful suckers near the actinostome, which are but slightly 
developed above the ambitus ; we find no fimbriated actinal tentacles, even 
in the largest specimens collected, measuring 12 mm. in length, so character- 
istic of the Spatangoids proper. The bourrelets arc well developed in speci- 
mens of 10 mm. in length, and in the largest specimen (12 mm. long) they 
have become very prominent. The lateral crowding of the anibulacral plates 
near the actinostome to form the phyllodes is well shown on comparing 
the arrangement and size of the plates as seen from the interior of the test 
