458 THE DEPTHS OF THE SEA. (CHAP. Ix. 
Desor, which makes the disjunct arrangement of the 
ambulacra at the apex the test character of the 
Dysasteridee, this genus should be referred to that 
group, for the apical disk is truly decomposed as in 
Dysaster and Cellyrites, and not merely drawn out 
as in Ananchytes. From the arrangement and form 
of the pore areas, however, and the general appear- 
ance and habit of the animal, I am inclined to think 
with Alexander Agassiz, that its affinities are more 
with such forms as Jnfulaster. Pourtalesia must be 
aberrant in whatever group it may be placed. 
The other genus Neolampas, A. AG., associates itself 
with the Cassidulidz in virtue of the nearly central 
pentagonal mouth with a tolerably distinct flocelle, 
the anal opening at the bottom of a deep posterior 
groove excavated in a projecting rostellum, the nar- 
row ambulacral areas, and the small compact group 
of apical plates ; but it differs from all known genera 
of the family, living or extinct, in having no trace of 
a petaloid arrangement of the ambulacra, which are 
reduced on the apical surface of the test to a single 
pore passing through each ambulacral plate, and 
thus forming a double row of alternating simple 
pores for each ambulacral area. I think I am right 
in identifying a single specimen, nearly 20 mm. in 
length, which we dredged in 800 fathoms water at 
the mouth of the Channel, with the species dredged 
by Count Pourtales at depths from 100 to 150 
fathoms, in the Strait of Florida, and described by 
Alexander Agassiz under the name of Neolampas 
rostellatus. 
Of the twenty-six Echinoderms dredged from the 
‘Porcupine,’ six—EHehinus flemingii, Echinus esculen- 
