352 Mr. H. J. Carter on 



of an inch (the value of that division of my micrometer-eye- 

 piece) for comparison, and they are intended to represent the 

 greatest dimensions longitudinally and transversely of the 

 average largest kinds approximately, as they very often vary 

 in this respect, not only in different specimens but in different 

 parts of the same specimen. When spined or differently 

 formed from the common type of both acerates and acuates, 

 this will be mentioned. 



Fam. 1. Ectyonida. 



Group 15. ECHINONEMATINA. 

 1. Echinonema flabelliformis, 



Stipitate flabelliform, like a clam-shell in general shape, 

 moderately thin, stem short. Consistence firm. Colour, 

 when fresh, "pale terra cotta," now brown. Surface even, 

 smooth, consisting of a minutely reticulated dermis spread 

 over a reticulated, cancellous, fibrous structure beneath. Pores 

 in the interstices of the reticulation. Vents in the margin 

 corresponding to the terminations of branched, radiating, 

 linear depressions on the surface, which originate towards 

 the stem. Spicules of three forms, viz. : — 1, skeletal, acuate, 

 55 by l-6000th in. ; 2, echinating, clavate, spined through- 

 out, 12 by l-6000th in. including the spines; 3, a small 

 acuate in tufts confined to the surface, 25 by |-6000th in. 

 Structure uniformly compact throughout, hardening generally 

 towards the stem, but not axially in any part. Size of 

 specimen Qy-Qx^ in. 



Depth 19 fath. 



2. EcMnonema ccGsjpitosa. 



Massive, sessile, spreading, with irregular proliferous cauli- 

 flower surface ; proliferous portions rising above the common 

 level into most irregular and jagged processes, great and 

 small, of variable size. Consistence firm, resilient. Colour, 

 when fresh, " brick-red," now sponge-colour. Surface uni- 

 formly granulated, supporting a smooth dermis. Vents on 

 the lobular projections. Spicules of three forms, viz. : — 1, 

 skeletal, acerate, cylindrical, nearly straight, almost immea- 

 surably thin, chiefly confined to the fibre, 45-6000ths long ; 



2, echinating, acuate, spined throughout, 20-6000ths long ; 



3, flesh-spicule equianchorate, naviculiform, bent upon itself, 

 3|-6000ths in. long. Structure columnar, compact, radiating 

 upwards. Size of specimen, 1^ in. high by 5 x 4 in. hori- 

 zontally. 



Depth 19 fath. 



