50 PLIOCENE MOLLUSCA. 



Fossil : Waltonian Crag : Walton-on-Naze, Little Oakley ; 

 probably at other horizons. 



Miocene : France, Italy. Pliocene : Sicily, Italy. Pleistocene : Sicily. 



Remarks. — I have a few specimens from Oakley, larger and more globose than 

 the typical forms of T. europsea, which correspond with some examples of T. 

 sj^hasi'ictdata I obtained from the Pleistocene deposits of Sicily. Prof. Sacco 

 remarks as to this form, tracing its descent from T. eiiropasa, var. r/lohnsa, that 

 though belonging clearly to the europsea group, with which it is generally 

 confused, it forms a species sufficiently distinct, an opinion shared apparently 

 by Seguenza. MM. Dollfus and Dautzenberg give it, however, from the Faluns 

 of Touraine as T. enropisea, var. splisericnlata, and I follow them as to the Crag 

 specimens. The latter seem to form a series connecting this Miocene shell 

 with the recent T. europsea, the principal difference between them being, as Wood 

 believed, one of size. 



Trivia aflBnis (Dujardin). 



1837. Cyprsea affinis, Dujardin, Mem. Soc. Geol. France, vol. ii, p. 304, pi. xix, fig. 12. 



1848. Cyprxa affinis, S. V. Wood, Mon. Crag Moll., pt. i, p. 16, tab. ii, fig. 9. 



1856. Cyprssa affinis, Homes, Foss. Moll. Tert. Wien, vol. i, p. 72, pi. viii, fig. 14. 



1873-5. Trivia affinis, Seguenza, Boll. K. Com. Geol., vol. iv, p. 204, 1873 ; vol. vi, p. 153, 1875. 



1886. Trivia affinis, Dollfus et Dautzenberg, Et. prel. Coq. foss. Tour., p. 13. 



1894. Trivia affinis, Sacco, Moll. Terr. Terz. Piem., pt. xv, p. 50, pi. iii, fig. 37. 



1898. Cyprasa (Trivia) europiea, var. affinis, A. Bell, Trans. Roy. Geol. Soc. Cornwall, vol. xii, p. 136. 



Specific Characters and Dimensions. — See Mon. Crag Moll., pt. i, p. 1(3. 



Distribution. — Not known living. 



Fossil : Coralline Crag ; Red Crag — Waltonian ; Newbournian. 

 St. Erth. Miocene : Touraine, Vienna, Italy. Pliocene and Pleistocene : Sicily. 



Bemarhs. — Of this well-known shell, characteristic of the Miocene deposits, 

 Wood states he had obtained two specimens only from the Coralline Crag, but I 

 have 50 or 60 from the Waltonian of Little Oakley, varying from 12 to 15 mm. in 

 length, and from 10 to 12 mm. in breadth, which I cannot distinguish from those 

 of the Faluns of Touraine. T. affinis is allied to T. europsea but differs from it in 

 having a well-marked dorsal sulcus, which in the Oakley shells is even more 

 distinct than in the one figured by Wood. It differs from T. avellana by its less 

 globose form. The latter species is not very common at Oakley, but this may be 

 accidental, as it occurs not infrequently in other Red Crag localities. 



Trivia pisolina (Lamarck). Plate II, fig. 17. 



1810-22. Cyprsea pisolina, Lamarck, Ann. Mus. Hist. Nat., vol. xvi, p. 108, 1810; Hist. Nat. Anim. 



sans Vert., vol. vii, p. 408, no. 17, 1822. 

 1886. Trivia pisolina, Dollfus et Dautzenberg, Et. prel. Coq. foss. Fal. Tour., p. 13. 



