312 PEOP. T. Pv. JONES OIT THE OSTEACODA 



Having been enabled, by the help of the Eev. 0. Eisher, Mr. W, 

 Cunnington, Mr. Horace B. Woodward, Mr. J. C. Mansel-Pleydell, 

 Prof. J. F, Blake, and other friends, to add considerably to my own 

 collection of Purbeck Entomostraca, among which are many spe- 

 cimens collected by Eitton and Brodie, and having been kindly 

 aided in my practical work by Mr. E. T. IS'ewton, E.G.S., and Mr. 

 C. D. Sherborn, I have begun to examine and determine the whole 

 series of Ostracodous species characteristic of the Purbeck-AYealden 

 beds. As far as opportunities have offered, I have also studied the 

 specimens preserved in other collections and museums. 



§ II. The Osteacoda of the Ptjebece: Beds. 



Sources of Information. 



Professor Edward Eorbes commenced this work of determining 

 the Purbeck Ostracoda long ago*; but his results were not fuUy 

 recorded, nor, indeed, is it now possible (as already intimated in 

 the papers referred to above) to recognize each of the typical spe- 

 cimens he intended to be preserved, or all the species that he 

 intended to determine, although a near approximation, on the 

 whole, has been obtained. 



The chief aids in this inquiry have been: — (1) The woodcut 

 figures in Sir Charles LyelFs 'Manual of Elementary Geolog}^' 

 5th edit. 1855, and in later editions, copied presumably from 

 diagrams made (between 1851 and 1855) for Prof. E. Eorbes by his 

 brother, James Eorbes, for his lectures at the Museum of Practical 

 Geology; (2) Some of these diagrams now remaining in that 

 Museum ; (3) Some hand-specimens in the same Museum, with 

 names given by E. Eorbes attached to them ; (4) Two MS. notes, 

 containing rough sketches by E. Eorbes, one not fully dated, but pro- 

 bably written on July 18th, 1851, and sent to Mr. Bristow (with 

 which he has most kindly favoured me), and the other to myself, 

 dated July 23rd, 1854. 



Sir C. LyelVs Woodcuts, and the Diagrams at the Museum, of 

 Practical Geology. — Erom the figures and accompanying remarks in 

 Lyell's 'Manual' &c., 1855, p. 294 &c., and the next edition of 

 the same work, with the title of ' Elements of Geology,' 6th edition, 

 1865, pp. 378 & 387, we find that 



1. "- Cypris-f gihhosa," fig. 368, a, 



2. " tuherculatcc," fig. 368, 6, 



3. " leg^iminella," fig. 368, c, 



are referred to the " Upper Purbecks ;" 



* Eeport Brit. Assoc, for 1850, Trans. Sect. pp. 79-81 ; and Edinb. New 

 Phil. Joiirn. vol. xlix. 1850, pp. 311-313. No names of the species are given in 

 either of these publications. 



t " C^pris" is far from being the genus to which all these Ostracoda are 

 really referable. The generic relationships will be discussed later on in this 

 paper. On these points my friend Dr. George S. Brady has favoured me with 

 his advice and opinion. 



