260 Explanation of the Plates. 



Fig. 5. A. B. Donacites Saussuri. A. Br. 



I presume that this is a donax, but I am far from being 

 certain. The form does not sufficiently shew it. The ge- 

 neric appellation should only be considered as provisional. 

 (Coll.ofDeluc.) 



Fig. 6. A. B. Donacites Alduini. A.Br. 



The figure is made from a tolerably entire and well pre- 

 serTed individual from Writhenterton in England, and which 

 I consider perfectly resembles the shells collected at Cap la 

 Heve by M. Audouin, and by other naturalists in the upper 

 marls of the Jura. It has much more the form of a donax 

 than the preceding species, and even resembles the Venus 

 meroe of Linn. I believe that this shell has been figured by 

 Knorr among the Cmusculites) t. il. pi. B, 11, 6**, fig. 5. 



Fig. 7. A. B. C. Cardium Protei. A. Br. Seen on three 

 sides. 



Though rather common in the upper marls of the Jura 

 formation, I do not know it any where exactly figured or 

 systematically named. The individual figured is from Cap 

 la Heve. 



Fig. 8. A. B. C. Hemicardium tuberculatum. A. Br. 



It slightly resembles the shell figured by Sowerby, pi. 143, 

 by the name of Cardita tuberculata, and those figured by 

 Knorr, tome 11. 1, tab. B. 1, a, fig. 2.4; yet there is a 

 difierence. M. de Schlotheim first cited these shells of 

 Knorr in the seventh year of the Taschenbuch, &c. of Leon- 

 hardt, by the name of bucardites reticulatus, and he after- 

 wards cites them in his Petrefacten Kunde, &c. (published 

 in 1820) p. 209, by the name of bucardites hemicardius. 

 It will be easily seen why I have not admitted these specific 

 names; the individual figure was sent me by M. Risso, it 

 comes from the Cap St. Hospice, near Nice. 



Fig. 6. A. B. C. Spatangus oblongus. Deluc. 



M. Deluc sent me this name with this species, which 

 occurs in the upper marls of the Jura. I conceive that the 

 spatangus which I collected in the same marls, behind the 

 town of Neufchatelj does not sensibly differ from it. It also 



