338 Prof. T. R. Jones and Dr. H. B. Holl on the 



Introduction. 



In the Ann. & Mag. Nat. Hist. ser. 2, vol. xvi. 1855, 

 pp. 81 et seq., one of us gave a short history of this genus and 

 a description of its characters *. Excepting that the group 

 " Beyrichice simpUces'''' now belongs to our genus Primitia^, 

 tliere is not much to alter in the account there given, though 

 many species have been added from several of the stages of 

 the Palseozoic system of strata. We may remark, however, 

 that we now prefer to regard them, together with Leper ditia, 

 as more closely related to Ostracoda J than to Phyllopoda, to 

 which order they were then referred with doubt (p. 85). 

 Doubtless they are an ancient generalized group possessing 

 characters since distributed among more special forms. The 

 '-'• Cyilierce'''' and '•'' Gytheropses'''' mentioned at p. 84 are pro- 

 bably Gytherids or marine Cyprids and Primitim) and the 

 B. siliqua (pp. 84 and 90) is a Cytlierellina (Ann. & Mag. 

 Nat. Hist. ser. 4, vol. iii. p. 215). 



It is important to notice an omission at p. 83, where it 

 should have been stated that Dr. Ernst Boll, of Neubran- 

 denburg, proposed '•'■Beyrichia " in 1847 as a name for the 

 genus independently of Prof. F. M'Coy, both having recognized 

 that Prof. Beyrich first referred these little fossil organisms 

 to their right systematic group. Dr. E. Boll § added much 

 to our knowledge of the Upper- Silurian BeyricMce from the 

 erratic blocks of Scandinavian limestones in North Germany. 



Since 1855 the BeyricMm have been much studied. The 

 observers have been Boll, 1856 and 1862 ; Schmidt, 1858 ; 

 Romer, 1858 ; James Hall, 1859 (also before and afterwards) ; 

 d'Eichwald, 1860; Billings, 1866; Bock, 1867; Ileiden- 

 hain, 1869; Richter, Kolmodin, Linnarsson, and Karsten, 

 1869; Barrande, 1872; Krause, 1877 ; Haupt, 1878; Brog- 

 ger, 1882 ; Kiesow, 1884 ; Renter, 1885. These, besides 

 others, including J. W. Kirkby and ourselves, have described 

 and illustrated new or little-known forms. A very full 

 account of the history of the genus up to 1872 will be found 

 in the late M. J. Barrande's Syst. Sil. Boheme, vol. i. Suppl. 

 1872, pp. 484 et seq., worked out with his usual accuracy and 



* See also the Proc. Geol. Assoc, Pal. Biv. Entom., 1869, pp. 8, 11, &c., 

 and the Monthly Miciosc. Journ. vol. iv. 1870, p. 192. 



t Ann. & Mag. Nat. Hist., Dec. 1865, pp. 415 &c. 



j Monthly Microsc. Journ. /. c. pp. 189-191. See also M. Barrande's 

 remarks to the same efi'ect in his Systeme Silur. Boheme, vol. i. Suppl. 

 1872, p. 467. 



§ This hard-working- enthusiastic naturalist died January 20th, 1868, 

 aged 51, much regretted by the members of the Natural-History Society 

 ot Mecklenburg, whose Journal he had edited for many years. 



