XCV111 PROCEEDINGS QF THE GEOLOGICAL SQCIETY. 



The carapace is nearly regularly oval — the anterior extremity 

 being widely notched, and the posterior slightly acuminated : it is 

 depressed as in the genus Platemys. The breastplate is solidly fixed 

 to the carapace for about half its length, the free portions being both 

 much narrowed, the anterior one subtruncated, and the posterior 

 one acuminated. 



M. Pictet describes in detail the bony pieces according to their 

 respective positions, and as far as the condition of the specimen 

 permits, and then, having made the most of his materials, discusses 

 the affinities of the species. In respect to the genus, he considers 

 that it belongs, without doubt, to the family of Elodites of Dumeiil 

 and Bibron, but states that it is impossible to refer it more specially 

 to any of the numerous genera of the family, as the generic characters 

 of most of them are based on portions of the bony structure of the 

 animal not preserved in the specimen, whilst, although clearly sepa- 

 rated from some others by the solid manner in which the carapace 

 and breastplate are joined to each other, there are not sufficient 

 data for separating it from others. Under these circumstances M. 

 Pictet thinks it prudent to retain for it the name of Emys, as ori- 

 ginally defined by Alexander Brongniart, in 1803, when it em- 

 braced the whole family of Elodites. M. Pictet gives, however, the 

 following diagnosis as a guide to palaeontologists in estimating the 

 value of the generic characters. 



" Bony case flattened ; breastplate extensively and firmly anchy- 

 losed with the carapace, without moveable pieces, perforated with 

 two holes, narrow and subtruncated in front, terminated behind by 

 a front not notched ; a series of submarginal scales between the 

 marginal scales and the sternal as well as the inguinal margins on 

 each side ; upper face of the marginal pieces very large, cut by the 

 margino- costal impression very near its exterior edge." 



In respect to species, M. Pictet considers that it approaches nearest 

 to Pleurosternon latiscutatum, Owen, known only from the carapace ; 

 but he points out several striking differences which separate it from 

 that species, although he thinks it probable that both species belong- 

 to the same generic type, and that the discovery of the breastplate 

 of Professor Owen's species might lead to its removal from the genus 

 Pleurosternon. He explains also the many points of difference 

 between the Emys Etalloni and the E. Menkei, Eoemer, and Platemys 

 Mantelli, Owen. It is therefore an interesting addition to the fauna 

 of the Upper Oolite period. 



In addition to the work I have just noticed of MM. Pictet and 

 Humbert, M. Pictet has published during the year the 6th, 7th, 8th, 

 and 9th parts of his contributions towards Swiss Palaeontology,— 

 being a series of Monographs of the Possils of the Jura and of the 

 Alps. A brief abstract of the species described, and of the localities 

 in Switzerland and in other countries where they have been dis- 

 covered, will explain in the simplest manner the value of these por- 

 tions of a very important work ; and it may be fairly said that the 

 fact of finding so many mollusca common to England, Prance, and 

 the limited localities of Perte du Rhone and Sainte Croix, is of even 



