256 ECHIXOLAMPIDtE. 



drawings of tins species, and of which he has given details all magnified six diameters. The 

 ambulacra are narrow and subpetaloid and the pores in the zones are small, equal, and 

 non-conjugate. The surface of tlie test is covered with scrobiculated tubercles, which are 

 large in proportion to the size of the shell ; these Avith the thickness of the test serve to 

 obscure the details of its structure. 



The apical disc, which is likewise the vertex, is placed a little before the centre, and is 

 composed of four perforated genital and five ocular plates, and the spongy body projects 

 towards the middle of the disc. 



The large triangular vent is situated at the under side of the projecting rostrum, fig. 2 c\ 

 d, e, and is so completely infra-marginal that the aperture cannot be seen from the upper 

 surface. The great development of the intra-ambulacrum which produces the rostrum 

 fomis one of the most marked characters of this species, fig. 2 c, and serves to distin- 

 guish it from the congeners. 



The base is convex and pulvinate ; it is a little depressed near the middle, where the 

 oblique mouth-opening is situated, fig. 2 c; the lines of zone-pores are here visible, and 

 the scrobiculated tuljercles are even larger than on the upper surface. 



Affinities mid Dijfcrences. — This species resembles C. trirjonopygus, but is distinguished 

 from it by its long recurved rostrum, fig. 2 c. The shell is likewise more inflated and the 

 base more convex. 



LocnUiij and Stratigrapliical Position. — This species is found only in the Upper 

 Greensand near Warminster, Wilts. In France it is likewise special to " I'Etage Ceno- 

 manien," or the " Craie Chloritee," from whence it has been collected at Havre, 

 Seine-Infcriem'e, at Fourras, Charente-Inferieure, and at Vaches-Noires, Calvados. 



Family 10 — Echinolampid^, Wright, 1856. 



Test thin, oval, oblong, elevated, or subdiscoidal ; ambulacral areas large, petaloidal -, 

 poriferous zones wide, pores distant, united by sutures, and extending nearly to the 

 margin. 



Mouth-opening small, subcentral ; peristome smTounded by five prominent lobes, and 

 always by a well-developed pentaphylloid floscelle. 



Vent oval transversely and infra-marginal. 



Apical disc very small, excentral, and composed of four perforated genital and one 

 imperforate plate, with five minute oculars wedged into the circumference of the disc. 



Plates of the upper surface covered with several rows of numerous small, closely set 

 tuljercles encircled bv sunken areolas. 



A few species are now living in warm seas ; the greatest number are extinct, and 



