WOODWARD — Otf ECHINOTHUltIA FLORIS. 



329 



by the Eev. N. Glass, who has cleared it from the matrix with great 

 skill and patience. It is represented by the figure marked D, and con- 

 tains the dental apparatus, or " lantern," and portions of several series of 

 imbricating plates radiating from it. At first sight, this specimen would 

 seem to solve the problem, by supplying the peristome and lantern of the 

 same great Cyphosoma or Diadema, of which Mr. Flower's specimen might 

 be the apex or periproct. But a closer examination confirms the objec- 

 tions already stated, and gives increasing probability to the other conjecture 

 (if, indeed, it does not compel us to adopt it), however difficult it may be 

 to realize the notion of an Echinite having no proper "test," and clothed 

 entirely with imbricating scales like those of the peristome of Cidaris. 



In Mr. Flower's specimen (A) the imperforate plates imbricate towards 

 the centre (or apex, a), where the smaller ends of the several series con- 

 verge. In Mr. Glass's specimen they slope away from the centre (or 

 mouth), that is, also towards the apex. The perforated or ambulacral 

 plates, which overlap one another outwardly (i. e. downwards) in specimen 

 A, are seen in B sloping towards the dental cone, and reclining upon it. 

 The portion of an ambulacrum situated between the letters a, b, c (in B), 

 consists of seven plates, diminishing in size from c to a, in a line not ac- 

 curately directed towards the centre. This portion exhibits the interior 

 surface of the plates, known by their curved surfaces, destitute of orna- 

 mental granules ; it is not, however, the oral end of one of the segments turned 

 over, a thing scarcely possible to happen, for in that case the dip of the plates 

 would be reversed, but it must be the opposite (or apical) extremity of a 

 series folded back upon its origin, and exposed to view by the damage 

 which the surface of the specimen has sustained. From this circumstance 

 it seems probable that the whole fossil, when complete, was not elongated 

 nor even spherical, but somewhat depressed in a vertical direction, though 

 doubtless admitting of a moderate amount of flexure. At the last hour, 

 after making the drawing, I ventured to clear away the chalk from the 

 side of Mr. Glass's fossil (near the letter i), where an ambulacral segment 

 is seen to curve as if it might be continued round to the other surface. 

 This attempt was successful, for the ambulacrum and also the adjacent 

 interambulacral segment (k) were found continuous, though crowded and 

 displaced at the turning, falling again into regular order, and diminishing 

 in size, though not so nearly complete as in Mr. Flower's example. 



After this apparently conclusive demonstration, it appears desirable to 

 give a name to the fossil, and to attempt a short description, although its 

 rank and affinities are to us still matter of conjecture. At present it is one 

 of those anomalous organizations which Milne-Edwards compares to soli- 

 tary stars, belonging to no constellation in particular. The disciples of 

 Von Baer may regard it as a " generalized form " of Echinoderm, coming, 

 however, rather late in the geological day. The publication of it should 

 be acceptable to those who base their hopes on the "imperfection of the 



VOL. VI. 2 u 



