NTJCULANA. 349 



margin straight, but sharply sloping upwards posteriorly; surface 

 having concentric strias and lines of growth ; lunula elliptical, 

 striated ; ligament pit internal, directly under the umbo ; cardinal 

 teeth very numerous. 



Professor Tate's interpretation of the immature shell figured 

 by Tenison- Woods, in the memoirs above cited, is here accepted. 



Dimensions. — Height 10"5 mm. ; length 17 mm. 



Form, and Loc. — Eocene : River Murray cliffs, South Australia. 



L. 9858. Several examples of both valves. Purchased. 



Nuculana acinaciformis, Tate (sp.). 



1886. Leda acinaciformis^ Tate, Trans. Eoy. Soc. South Aust. vol. viii. 

 p. 130, pi. V. figs. 6a-i. 



Shell more elongate posteriorly than N. t'agans, ventral margin 

 gracefully curved, not so solid, hinge-line narrower ; exterior of the 

 shell equidistantly deeply striated, posterior keel conspicuous ; 

 lunule lanceolate, longitudinally ridged. 



Dimensions. — Height 12 mm.; length 23 ram. 



Form, and Loc. — Miocene : Muddy Creek, Victoria. 



L. 4799. Right valve. Presented by John Dennant, Fsq. 



L. 6602. Examples of both valves. Purchased. 



L. 9820. Specimens of the brephic and neanic stages of growth. 



Purchased. 



Nuculana woodsi, Tate (sp.). 



1879. Zeda inconspicua, Tenison -Woods, Proc. Linn. Soc. N.S.'W. vol. ui. 



p. 139, pi. xxi. fig. 3 {lion A. Adams). 

 1S86. Leda woodsii, Tate, Trans. Eoy. Soc. Soutti Aust. vol. viii. p. 133, 



pi. is. fig. 8. 

 1893. leda woodsi, Tate and Dennant, id. vol. xvLi. pt. 1, p. 224. 



Allied to i\^. varans, from which it differs in having an arcuate 

 (instead of a straight) ventral margin, a somewhat less elongate and 

 biangulate posterior rostrum, in being closely, evenly, concentrically 

 striated on the surface, and in having a distinct posterior curved 

 keel commencing at the umbo, between which and the posterior 



