Dr. H. Woodimrd — On Meyeria Willettii. 557 



enables me to refer to the same species about eight other remains 

 from the Chalk preserved in the British Museum and including the 

 carapace figured on pi. xxxviii. fig. 8 of Dixon's Geology of Sussex. 



M'Coy considered Meyeria to belong to the family Thalassinadce : 

 but to this Prof. Bell demurs, considering it ought to be associated 

 ■with the Astacidce, the division across the exterior plate of the tail 

 being an absolutely distinctive character of the latter family. 



It will be observed that Mr. Willett's specimen, figured in the 

 annexed woodcut, agrees more nearly in size with Meyeria ornata, 





^^^ 









^^ <s^ 



LJ' /^L. 



^ 



WM- 



^\r- 



r^w^T 



\.M» 



J 



\ 







' 



J 



Meyeria Willettii, H. Woodw. White Chalk, Lewes. Natural size. 



from Speeton, than with the much larger species, Meyeria vectensis, 

 from Atherfield. The abdominal somites of our specimen, however, 

 are not ornamented, as in M. ornata, with four or five transverse 

 elevated I'ows of rounded granulations, but are nearly plain, as in 

 M. vectensis, save that each segment is marked by two lateral grooves 

 enclosing a somewhat raised area, and their epimera are granulated 

 and furnished with small spines along their border, which is trun- 

 cated. The median lobe of the tail is wanting, but two lateral lobes 

 are present, the outer of which is transversely divided along the 

 distal border. The carapace is evenly and finely granulated ; the 

 cervical furrow is nearly straight, dividing the carajDace at about one 

 third of its length from the front ; the cardiac furi'ow is clearly 

 marked, enclosing a broadly triangular area, the sides of which slope 

 upwards on either hand from the cervical furrow, and meet upon the 

 dorsal line near the posterior margin of the carapace. 



Three nearly parallel ridges, with slightly more prominent 

 granules, mark the gastric region of the carapace. A furrow, 

 uniting with the cervical and cardiac furrows, curves around the 

 hepatic region, and separates it from the other regions of the 

 carapace. This part is very indistinct in Mr. Willett's specimen, 

 but is well shown in the carapace figured by Dixon. 



From Mr. Willett's specimen, and still more clearly marked in 

 one of Dr. Mantell's, we learn that the forearms were long, slender, 



