The Invertebrate Fauna of the Uitnilitige Series. 137 



ridges are absent in the adult, and the interior of the valve-margin is 

 strongly crenulated. 



Astarte rhodani Pict. and Camp.,* from the " Gault" of the Perte- 

 du-Khone, is of similar general type, but is truncated posteriorly. 

 Shells from the Gault of Cosne (Nievre) figured by de Loriolf under 

 the name A. rhodani have a much more closely similar, rounded 

 outline; they appear, however, to have a slightly shorter lunule, and 

 they are probably without marginal crenulation. 



Astarte dupiniana d'Orb.J from the Albian of Prance, closely 

 resembles A. rhodani Pict., and like this, is abruptly truncated 

 posteriorly ; in this it offers a contrast to the more rounded profile of 

 A. pinchiniana. A. dupiniana possesses the character of marginal 

 crenulation, but differs from the African shell in having a less 

 strongly developed lunule and escutcheon. 



The presence of well-developed sculpture in the neanic stage of 

 A. pinchiniana and its disappearance in the succeeding growth- 

 stages, indicates degeneration, so far as this character is concerned, 

 from a wholly sculptured ancestry. 



GENUS ANTHONYA W. M. Gabb. 



ANTHONYA LINEATA sp. nov. 

 Plate VII., figs. 7, 8. 



Description. The shell is of slender, elongated form, much pro- 

 duced posteriorly. The valves are flattened and compressed, having 

 very slight convexity. The umboiial region is not strongly pro- 

 minent ; it is situated at a distance of about one-third of the shell's 

 total length from the anterior extremity, where also the shell has its 

 greatest height. The upper valve-margin, posteriorly to the umbo, 

 slopes down gradually, giving a very slightly concave outline. It has 

 an angular junction with the siphonal margin. The siphonal margin 

 is very short and shows a straight outline, directed slightly pos- 

 teriorly when traced down to its inferior termination. In front of 

 the umbo, the valve-margin is at first forwardly produced with a 

 downward slope and straight outline, passing then by a curve into 

 the convex anterior margin. This in turn passes by regular curve 

 into the elongated, slightly convex inferior margin. The siphonal 



* Pictet and Campiche (1), 3 e Partie, p. 319 (1866) ; Pictet and Eoux (1), p. 437, 

 pi. 32, fig. 5 (1852). 



t de Loriol (4), p. 94, pi. xii., figs. 1-7. 



t d'Orbigny (3), p. 70, pi. 264, figs. 4-6 (1844). 



