608 PLIOCENE ^^lOLLL'SCA. 



Jeffreys points out {oj). cit.,\o]. iv. p. 11) tliat the Ti(rho cimec of Donovati 

 and Montagu is a different species. 



Alvania fenestrata (Etberidge and Bell). Plate L, fig. 46. 



1893—98. Bissoa fenestrata, A. Bell, Pr^>c. Key. Irish Acad. [3]. toI. ii, p. 6l9, 1893; Traus. Roy. 

 Geol. Soc Cornwall, toI. xii, p. 152, 1898. 



Specific Characters. — Shell minute, ovate, fairlv strong and solid; whorls 

 coDTex, the last tumid, much the largest, two-thirds the total length ; ornamented 

 by numerous distinct and rounded costae, placed close togetiier, occupying the upper 

 pai"t only of the body- whorl, and by strong spiral ridges below ; spire verj' short, 

 rapidly diminishing upwards to a blunt and rounded point ; suture deep ; mouth 

 ovate, expanded, large in proportion to the size of the shell ; base of inner lip 

 furnished with a prominent umbilical chink. 



Dimensions. — L. 1 mm. B. 1 mm. 



Distribution. — Not known living. 

 Fossil : St. Erth. 



ffemarks. — The St. Erth fossil here figured is from the Warburtou Collection at 

 the British ^luseum, and has been identified by Mr. A. Bell as the one found by 

 him and described bv Mr. Etheridsre and himself under the above name. It is a 

 distinct form with comparatively coarse sculpture ; in Mr. Bell's opinion it is the 

 only example that has been found. 



Alvania Cossmaani, A. Bell, MS. Plate L, fig. 47. 



Specific Characters. — Shell minute, ovate, solid ; whorls convex, the last ventri- 

 cose, much the largest; ornamented by very fine but distinct reticulate sculpture 

 on the upper part of the last whorl ; on the base and on the lower part by rather 

 strong spiral ridges; spire short; mouth subcircular, expanded; suture clearly 

 marked. 



Dimensions. — L. 1 mm. B. 1 mm. 



Distribution. — Not recorded livincf. 

 Fossil : St. Erth. 



Remarlcs. — The shell fiarnred under this name was found bv ^Ir. Bell, but has 

 been left unrecorded in his collection at the British Museum. It is one of the 

 smallest of the St. Erth Rissoas, but it looks like a mature specimen. 



Alvania crassi-striata (^>. V. Wood). Plate L, fig. 49. 



1842 — 48. Riseoa cragsi-ttriata, S. Y. Wood, Ann. Mag. Nat. Hist. (1), vol. is, p. 533, 1842 ; Mon. 

 Crag MolL, pt. i, p. 106, pi. xi, p. 13, 1848. 



