FROM THE UPPER GREENS AND. 159 



them. The vent is raised on an eminence which is directed backwards. The anal opening 

 is transversely oval, and the periprocte forms a thickened bourrelet, which is oblong in the 

 variety fig. 1 a and angular in fig. 3. In both figures the apical disc is magnified fonr 

 ,)diameters. 



The base of the test is flat, and the mouth opening small, about one third the diameter 

 of the test. The specimens figured in figs. 2 and 3 have been kindly communicated by 

 W. Cunnington, Esq., E.G.S., as remarkably well marked forms of this species. 



Affinities and Differences. — The test of P. umbrella closely resembles that of F. 

 clathratus, the difierence chiefly residing in the form and structure of the apical disc, which 

 can be much better understood by a comparison of the figures in PI. XXXII, fig. 2, and PI. 

 XXXIV, fig. 1 a, fig. 1 b, fig. I d, and fig. 3, and to which we must beg to refer the 

 reader. 



Locality and Stratic/raphical Position. — The type specimen was collected from the 

 Upper Greensand near Warminster, associated with Peltastes clathratus in the same 

 stratum. 



Peltastes Bunburyi, Forbes, sp. PI. XXXIX, fig. 2 a — i. 



Salenia Bunburyi, Foi-bes. In Morris's Catalogue of British Fossils, p. 89, 1854. 

 — — Woodward. Mem. Geol. Surv., App. to Decade V, p. 6, 18.56. 



Diagnosis. — Test subglobose, much elevated, sides tumid, base wide and flat ; oral 

 aperture depressed ; apical disc large, very deeply indented at the border, between the 

 ocular and ovarial plates ; a series of ten elliptical ridges with central depressions formhig 

 an ornamented pentagon on the disc ; sur anal plate with two pairs of oblique elliptical 

 ridges. Vent large, diamond-shaped, excentral, looking obliquely backwards, with a 

 thickened periprocte. Ambulacra narrow, slightly flexed, with small remote marginal 

 tubercles, separated by a prominent ridge of microscopic granules. Inter-ambulacra wide ; 

 three prominent tubercles at the ambitus, and four srafiller near the base ; upper surface 

 covered with scattered granules. 



Dimensio?is. — Height, half an inch ; transverse diameter, thirteen twentieths. 



Description. — The original and unique specimen of this Salenia was presented to the 

 Museum of the Royal School of Mines by E. H. Bunbury, Esq., M.P. My late lamented 

 colleague Professor Edward Forbes named this Urchin, without leaving any notes of its 

 specific characters. A brief diagnosis of these were given by my late friend Dr. Woodward 

 in his appendix to the fifth Decade of the Organic Remains in the Memoirs of the 

 Geological Survey. It is now figured for the first time. 



The test is subglobose and much elevated (fig. 2 a — d), inclining to a conical form. 

 The ambulacral areas are narrow, and slightly flexed with two rows of small remote 

 marginal tubercles, sixteen or seventeen in each row. These are separated by a median 

 ridge formed of microscopic granules, which fill up all the space unoccupied by the tubercles. 



