from the Loiver Greensand. 537 



often joined to the scrobicular ring by a low ridge. Tertiary 

 tubercles of almost equal size to the secondaries, alternating witb 

 them, and often intruding into their circle. Miliaries fine, rarely 

 more than one row outside the tertiaries. 



Var. major, nov. — Siraildr to var. typica, but constantly larger. 

 Miliaries numerous, arranged in transverse sei'ies, separated by sulci 

 on the ambital plates. 



Radioles. — Long, cylindrical, inflated on one side. Stem covered 

 with coarse, partially confluent granules (most marked on the inflated 

 side), which increase in size gradually from the collerette until, near 

 the distal end, they fuse into carinae, terminating in a pronounced 

 corolla. Collerette short, undefined distally. Annulus prominent, 

 base large. Acetabulum deep, with a smooth margin and large 

 central perforation. 



Description : General Characters. — A very beautiful complete 

 specimen has recently (1912) come into the possession of 

 Mr. Treacher. It has many secondary radioles adhering to its 

 surface, and remains of the apical system are preserved in situ. 

 Since the surface of the plates is rather encrusted, it seems better 

 to describe the structural details from other examples. There are 

 several connected fragments of this species in Mr. Treacher's collection, 

 and all offer identical characters. They all represent rather small 

 specimens of var. typica, but otherwise agree perfectly with the 

 abundant isolated plates of both larger and smaller size. The 

 complete specimen is the holotype. The original of PI. XXVI, 

 Fig. We, is the type of the radiole. The diagnosis and description 

 of the species are generalized from over 200 plates and a far greater 

 number of radioles. In case it should be shown that the fragments 

 do not all belong to the same species, the name coxioellensis should be 

 applied to the test. 



The complete corona is somewhat depressed in shape. The 

 diameter of the holotype is 25'5 mm., and its height 16 ram. 

 The average size woukl seem to be about one and a half times as 

 great as this, judging from the dimensions of the isolated plates. 



The Apical System. — One or two fragments of both ocular and 

 genital plates occur in the holotype, but their characters, beyond 

 that of a fine superficial granulation, are not well shown. The 

 diameter of the apical disc is smaller than that of the peristome 

 (12 mm. as against 13-2 mm.). 



The Corona: Inter amhulacr at Plates. — Average adult specimens of 

 var. typica from the adapical region measure about 8'3 mm. longi- 

 tudinally and 7"1 in their greatest breadth. The outline of the 

 plates is thus proportionately taller than those of C. faring donensis. 

 The scrobicule is wide, circular, shallow, and near the adoral margin 

 of the plate. The basal terrace is obscurely visible. The boss is 

 central, often concave in section, sometimes dome-like, rising to a plat- 

 form with a diameter less than a third the width of the scrobicule. 

 The platform is practically flat, with no parapet, and is entirely 

 uncrenelated. The mamelon is very large, of equal diameter with 

 the platform, Avhicli is only visible under the undercut neck of the 

 mamelon. The central perforation is relatively small. The scrobicular 



