52 R.. BULLEN NEWTON on 



with well circumscribed walls marked by roundly excavated lines of growth 

 but without spiral ridges ; aperture depressed, ovate, inner lip-margin deeply 

 excavated ; agglutinations of comminuted shells &c. occur in the neighbourhood 

 of the suture and at the periphery. 



DIMENSIONS. 



Alt. ... ... ... ... ... 10 millimetres. 



Diam. ... ... ... ... 17 



REMARKS. This small species varying in diameter from 5 to 17 mm. is 

 quite well represented, and at first sight appears to be Lamarck's T. agglutinans 

 from the Lutetian-Bartonian deposits of Europe, but that species has a smooth 

 base while the sculpture of the upper surface is much more irregular consisting of 

 longitudinally-oblique riblets rather than the regular spiral ornamentation 

 characterising the present shell. The presence of an umbilicus indicates that 

 this species belongs to Fischer's genus Tugurium of which Trochus indicus 

 of Gmelin of recent seas is the type. Some examples of this shell are 

 associated with Teredo tubes (see p. 102). 



OCCURRENCE. Cuttings Nos. 5, 6, 10, 12, 15. 

 COLLECTOR. Mr. Kitson. 



Family ARCHITECTONICID^ ( = Solariidas). 

 Stellaxis bicingulata, sp. nov. 



PLATE 5, figs. 10, 11. 



DESCRIPTION. Shell broadly conical, summit depressed, basal width about 

 twice the altitude ; whorls 7, smooth, depresso-convex, suture thin ; peripheral 

 border subangulate, with a narrow, slightly elevated cord-like circlet ; base 

 depressed prominently umbilicated, cavity deep, infundibuliform, reaching to 

 the apex ; aperture subquadrangular, angulose at periphery ; sculpture consisting 

 of very obscure, distant, spiral lines and numerous fine radial striations ; the 

 base possessing 2 cordiform cingulae the thicker forming the periphery, divided 

 by a narrow furrow, there are besides obscure spiral striations and numerous 

 radial lines of growth ; umbilical margins are strongly nodulated while the 

 internal walls are covered with fine vertical striations. 



DIMENSIONS. 



Alt. ... ... ... ... ... 12 millimetres. 



Diam, 24 



