CYPRICARDINIA. 
13 
as it comes from Barton, and I know of no other sliell at all like it from that 
locality, and as its general shape and ornament give the impression of identity, I 
am inclined to believe that the points of difference are due to the imperfection of 
his specimen or of his drawing, and that our shells must be referred to his species. 
It is to be remembered, moreover, that the anterior constriction often varies in 
intensity in other species of the genus. 
Hisinger^ previously described a different Silurian species under the name 
Avicula reticulata ; but, as Phillips's species belongs to a different genus, it may 
be allowed, in Professor Rupert Jones's opinion, to retain its trivial name. 
Tollman,^ who would unite it with A. anisota, Phillips, observes that Phillips's 
figure bears resemblance to a Gypricardinia. 
Affinities. — Sandberger® regards Phillips's Avicula reticulata as a synonym of 
Cypricardia elongata, d'Archiac and de Verneuil,* but from that shell it differs in 
its much fewer and coarser markings, its more elongate shape, and the contour of 
its post-umbonal line. 
It also approaches Cypricardia crenistria, Sandberger,^ of which Gypricardinia 
nitidula, Barrande (pars),^ is a synonym, but is distinguished by its greater length, 
its much smaller and less definite hind wing, its more defined post-umbonal line, 
its more produced and compressed inf ero-posterior corner, and its short and distant 
radiating strige. 
Cypricardia crenicostata, F. A. Romer,'' is a much squarer and less transverse 
shell. 
Gypricardinia alveolaria, (Ehlert,^ is a much shorter and more quadrate shell. 
4. Ctpricaedinia ensifoemis, Whidborne, sp. PI. I, figs. 14 — 16. 
1889. Ctpricardia ensipoemis, Whidborne. G-eol. Mag., dec. 3, vol. vi, p. 79. 
Description. — Shell small, flat, elongate, oblique, trapezoidal. Umbo appa- 
rently very small, recurved, facing forwards, proximate, flattened, situate near the 
1 1836-40, Hisinger, ' Leth. Suec.,' p. 57, pi. xvii, fig. 13 ; and 1839, Sowerby, in ' Murch. Sil. 
Sjst.,' p. 614, pi. vi, fig, 3. 
2 1885, Follman, 'Verb. d. nat. Vereins Bonn.,' Jahrg. 42; Verhdl., p. 204. 
3 1853, Sandberger, ' Verst. Ebein. Nassau,' p. 261, pi. xxvii, figs. 14, 14 a — e. 
* 1842, d'Archiac and de Verneuil, ' Geol. Trans.,' ser. 2, vol. vi, pt. 2, p. 374; pi. xxxvi, 
figs. 14, 14 a, h. 
' 1853, Sandberger, ' Verst. Ehein. Nassau,' p. 263, pi. xxviii, figs. 5, 5 a, b. 
8 1881, Barrande, * Syst. Sil. Boheme,' vol. vi, pi. cclvii, fig. 4, i— is only, Et. F. 
' 1850, F. A. Ecimer, ' Beitr.,' pt. 1, p. 60, pi. ix, figs. 20 a, b. 
8 1888, (Ehlert, * Bull. Soc. Geol. Fr.,' ser. 3, vol. xvi, p. 659, pi. xv, 6gs. 2, 2 a—d. 
