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 

 Dysasteridae, this genus should be referred to that 

 group, for the apical disk is truly decomposed as in 

 Disaster and Collyrites, 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 Infulaster. Pourtalesia must be 

 aberrant in whatever group it may be placed. 



The other genus Neolampas, A. AG., associates itself 

 with the Cassidulidse 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 

 6 Porcupine,' six Echinus flemingii, Echinus esculen- 



