16 PEOr. T. R. JOIJ^ES ON SOWE PALiEOZOIC OSTRACODA 



4. Beyrichia octjlina, Hall. (PI. I. %. 4, after the original 



drawing.) 



Beyrichia ocidina, Hall, ' Palaeont. New York,' vol. iii. 1859, 

 p 378 (pi. Ixxix. B, figs. 2 a-e ; not published). 



Size : length 2*3 mm., height 1*8 mm. 



This little Beyrichia to a considerable extent resembles B. Salte- 

 riayia *, Jones, having a neat symmetrical form, with a central and 

 two other lobes ; but the latter coalesce ventrally, and, according to 

 Dr. Hall's description, the posterior (largest) lobe is sometimes 

 crossed by a slight depression, and projects upwards above the 

 hinge-line. 



Prom the Pentamerus-limestone, Schoharie Co., N.-Y. State. 



5. Beyrichia Buchiana (?), Jones. (PI. III. iig. 25.) 



Size : length -43 mm., height '3 mm. 



This is a very small, not well-preserved, three-lobed Beyrichia. 

 The front lobe or ridge is free ; the middle lobe, curving ventrally, 

 probably joined the hinder ridge, which is divided into two unequal 

 parts, its upper (smaller) portion being round, and the lower part 

 pyriform. 



Beuter's Beyrichia tubercuIato-KocJiiana f has a somewhat similar 

 valve, but its middle lobe is short, and the hinder ridge is much too 

 large and tuberculate. Some varieties, however, of B. Bachiana, 

 Jones, figured and described by Kiesow as var. nutans X^ on account 

 of the strangulation of the top of the posterior ridge, supply a near 

 equivalent to the little form under notice. Hall's B. cequilate7'a, 

 from Arisaig, I^ova Scotia (as figured, Canad. Nat. Geol. vol. v. 1860, 

 p. 158, fig. 20), is like this, but the'free ridge is larger, and the central 

 lobe is very much smaller. 



Another form near to this is TJlnch's Beyrichia persulcata (Journ. 

 Cincinn. Soc. N. H. vol. vii. no. 1, 1879, p. 12, pi. vii. fig. 6) ; but the 

 latter has a ridge or lobe between the divided ridge and the margin. 



In the specimen, Brit. Mus. 59723 ; a thin limestone, largelj^ 

 made up of " L. cylindrica, Hall," obscure and imbedded, chiefly on 

 one plane ; L. mlnutissima, Hall, and Primitia Whit/ieldi, nov., are 

 also present. On one plane is the cast of a little ripple-mark, and 

 this small Beyrichia lies in it. — Cincinnati, Ohio. 



6. Beyrichia parasitica (Hall). (Woodcut, fig. 1.) 



Size : length 1-15 mm., height '625 mm. 



Mr. J. M. Clarke, of Albany, has kindly sent me a sketch of what 

 was probably intended for " Leperditia parasitica ,,^^ Hall, Paloeont. 

 New York, vol. iii. 1859, p. 376 (pi. Ixxix. a, figs. Sa,h; not published). 



* Ann.& Maer. Nat. Hist., August 1855, p. 89, pL v. figs. 15, 16; Krause, 

 Zeitschr. d. D. g. Ges. 1877, p. 35, pi. i. fig. YJa; Eeuter, op. cit. 1885, p. 645, 

 pi. xxvi. fig. 19 A a. 



t Zeitschr. d. D. g. Ges. 1885, p. 643, pi. xxvi. fig. 14 ; in this and in some of 

 his varieties of B. Buchiana it is the anterior lobe that is shown to be divided 

 into two parts. 



I Op. cit. 1888, p. 7, pi. i. figs. 11 and 14. 



