400 DR F. A. BATHER. 



two particulars : first in the absence of a strut ; secondly, in the fact that the top of 

 the leg, at the base of the tag and tongue processes (§ 164), is not enclosed, but is filled 

 with the wrinkled integument that surrounds the Vent. 



§ 168. The integument of the obverse face is attached to the edges of the marginals 

 on this face, in the same way as that of the reverse face, from which it differs in the 

 slightly greater fineness of its plating, accentuated towards the vent. 



§ 169. This face is further marked by the Subvective System, which differs from 

 that of all other echinoderms. In the toe-half is a peculiar area, at first suggestive of an 

 elongate pectinirhomb, lying alongside the frame from the stem to the toe. This area 

 is occupied by a number of short subvective grooves, approximately at right angles to 

 the adjacent frame. The number of these varies from about thirteen to forty-two, 

 according to the species and the size of the individual. Each groove is protected by 

 alternating cover-plates. In each groove, at the end furthest from the frame, a hole 

 leads to the thecal cavity. This is regarded as a mouth, opening into the gullet ; it 

 is bounded on the side away from the groove by a hood-shaped rim, and the groove 

 itself is bounded by a slightly-raised rim ; these two rims do not appear to have been 

 rigidly united. 



Discussion of the Habits of the animal and of the Relationships of the genus is 

 postponed till after the description of the species (§§ 223, 245). 



Cothurnocystis Elizae n. sp. 

 (Plate III. figs. 26-38. Text-figs. 14-23.) 



§ 170. Diagnosis. — A Cothurnocystis with outline of frame markedly boot-shaped ; 

 with integumentary plates normally flat and tessellate ; with subvective grooves of 

 elliptical outline, having diameters as 1 : 3, and occupying an area immediately adjacent 

 and parallel to the curve of the boot-sole. 



In naming this species, by permission, after Mrs Elizabeth Gray, I desire to 

 commemorate her zeal in collecting so rich a series, and her acumen in recognising the 

 peculiar shape and the Cystid nature of these extraordinary fossils. 



§ 171. Locality. — Thraive Glen, Girvan. 



§ 172. Horizon. — The Starfish Bed in the Drummuck Group (§ 6). 



§ 173. Material. — Sixty-six specimens, all in Mrs Gray's collection. G6 is taken as 

 .holotype (PI. III. fig. 28). 



The paratypes include the following specimens definitely referred to in the descrip- 

 tion : G3, GlO-14, Gl7, Gl8, G22, G23, G25-27, G31, G32, G34, G36, G39-43, G45, 

 G46, G50-59, G64, G267-269 ; also the following examined and referred with cer- 

 tainty to this species : G4, G8, G9, G 1 6, G 19-21, G28-30, G35, G44, G47-49, G65, 

 G66, G191. 



G204 (PI. IV. fig. 47) may be a portion of a young individual of this species. 



