174 SALENIA 



Greensaiid of "Wiltshire. The test is small and circular ; the upper surface convex, and 

 the base flat; the sides are inflated, and the disc conspicuous and prominent. 



The ambulacral areas are straight, with two rows of prominent homogeneous granules 

 on their margins, and oblique rows of small granulations, thi'ee in each, between every 

 pair of marginal granules (fig. 2/, 2 c). The pores are unigeminal, the pairs slightly 

 oblique, and the zones narrow and straight. 



The inter-ambulacral areas are wide, and the two rows of primary tubercles are placed 

 close to the pores, so that the miliary zone is wide and filled with granules of different 

 sizes (fig. 2 c) ; the tubercles are of moderate dimensions, and gradually decrease from 

 above downwards. Four of the five sides of each plate are encircled with a row of 

 mammillated granules (fig. 2/). 



The apical disc is large, solid, and prominent, the border gently undulated, and the 

 sutural lines soldered up ; in lieu thereof, there are three large punctuations between tlie 

 junctions of the three anterior ovarial and sur-anal plates, and between all the ocular 

 plates and ovarials ; the oviductal holes are large ; the vent is round ; the periprocte 

 thickened, ])rominent, and slightly excentral (fig. 2 a, 2 d). 



The mouth-opening is nearly half the diameter of the test ; the peristome is deeply 

 incised, and the lobes are nearly equal (fig. 2 b). 



Affinities and Differences. — Salenia Besori resembles S. gibba. It has, however, fewer 

 granules in the ambidacra, the inter-ambulacra are more regularly developed, the apical 

 disc is without sutures, and the mouth-opening is larger in proportion to the diameter 

 of the test. 



Locality and Stratiyraphieal Position. — This rare Urchin was collected from the Upper 

 Greensand near Warminster. I have dedicated it to my friend Professor E. Desor, of 

 Neuchatel, one of the learned authors of the ' Catalogue raisonne des fichinides ' and 

 ' Echinologie Helvetique,' and author of the ' Synopsis des Echinides fossiles ' and many 

 other valuable works on natural science. 



SalEiNIA gibba, Agassis. PI. XXXIV, fig. 4 a, b, c, d, e. 



Salenia gibba, Jgassiz. Monogr. des Snleniea, p. 13, pi. ii, figs. 9 — Ifi, 1838. 



— — Ayassiz ei Desor. Catalog, rais. des Echinides, Ann. Sc. Nat., 3e serie, 



t. vi, p. 341, 1846. 



— — Bronn. Index Palaiontologicus, p. 1107, 184". 



— — d'Orhigny. Prod, de Pal. strat., t. ii, p. 180, 1850. 



— — Morris. Catalogue of British Fossils, 2nd ed., p. 89, 1856. 



— — Piclet. Traite de Paleontologie, t. iv, p. 248, 1857. 



— — Cotteau. Paleontologie Frau9aise, Terrain cretace, torn, vii, p. 151, 



pi. 1035, figs. 13—20, 1865. 



Z>^ffy??oiM-.— Test small, circular, Upper surface inflated, gibbous, under surface flat, 



