SILURIAN OSTRACODA FROM NORTH AMERICA, ETC. 555 



of the characteristic fossils (with B. hussacensis, J., and Primitia 

 simplex, J. [P. mundula ?]) of the Upper Zone of the " Schistes 

 ardoisiers," belonging to Barrande's " Faune Seconde Silurienne " ; 

 also in Table B, opposite p. 636, as from Le Creux and Andouille *. 

 In the 'Bulletin Soc. Geol. France,' ser. 3, vol. iv. 1876, in the 

 memoir by MM. Gaston de Tromelin and P. Lebesconte on the 

 Primary Strata of the Department of lUe-et-Yilaine and other 

 parts of Brittany, B. Guillieri is referred to at p. 601. 



It may be a cast of a variety oiBeyricliia ciliata, Emmons (Q. J. G. S. 

 February No., p. 19), with a sketch of which Mr. E. 0. Ulrich has 

 kindly favoured me, and for which in a letter he has proposed the 

 new generic name of Ctenoholhina. 



It may be here noticed that in M. Lebesconte's collection there 

 are casts of another species of Beyrichia from the " Schiste ardoisier 

 inferieur " of Andouille (Dep. Mayenne), which approaches more 

 nearly to B. Kloedeni, M'Coy ; the lobes, however, are thin, the an- 

 terior and middle lobes nearly symmetrically curved, with an oval 

 sulcus between them, and the posterior lobe much smaller than that 

 of B. Guillieri. One of these specimens was referred by M. de 

 Tromelin, in the ' Bullet. Soc. Geol. France,' ser. 3, vol. iv. 1876, 

 p. 588, to B. reticulata, Bornemann, but they have no direct relation- 

 ship at all (see PI. XX. fig. 14, and page 539). 



From the same strata at Andouille there occur (in M. Lebesconte's 

 collection) Beyrichia bussacensis, J., ' Quart. Journ. Geol. Soc' vol. ix. 

 p. 160, pi. vii. figs. 5 & 6, and ' Ann. & Mag. Nat. Hist.' ser. 2, 

 vol. xvi. p. 169, pi. vi. fig. 14; also Primitia mundula, J., op. cit. 

 p. 174, pi. vi. figs. 28-31 ; a non-sulcate Primitia or Aparchites ; a 

 small Leperditia^ related perhaps to L. nana, J., op. cit. ser. 3, vol. i. 

 p. 244 (" L. canadensis, var."), pi. ix. fig. 12 ; and a Cytheroid form, 

 possibly a BytTiocyjpris, near B. symmetrica, J., op. cit. ser. 5, vol. 

 xix. p. 186, pi. vii. figs. 3, 4, 7. 



EXPLANATION OF PLATE XX. 



Devonian Ostracoda, with one (fig. 14) Silurian. 



Fig. 1. Beyrichia devonica, Jones. A cast of the inside of a crushed valve; 



one lobe partly worn away, a, left valve ; b, edge profile. Bos- 



phorus. X 12 diam. 



2. . a, left valve ; 6, edge profile. Devonshire. X 6 diam. 



3. . Right valve, obliquely squeezed. Devonshire, x 6 diana. 



4. Beyrichia suhquadrata, sp. nov. Left valve (reversed drawing of a 



hollow cast). Ontario Co., New York. X 15 diam. 

 6. Bollia Hindei, sp. nov. Left valve. Eighteen-mile Creek, Lake 



Erie, N.Y. X 15 diam. 



6. Beyrichia Kolmodini, sp. nov. Left valve. Clarke Co., Indiana. 



X 15 diam. 



7. Octonaria Linnarssoni, sp. nov. Carapace, a, left valve seen ; b, ven- 



tral view. Clarke Co., Indiana. Xl5 diam. 



* The Entomostraca mentioned as occurring in the same strata with B. Guil- 

 Zz£!ri I have not been able to recognize in the collection kindly submitted by 

 M. Lebesconte last year, excepting Bolhozoe anomala, B., and Beyrichia bussa- 

 censis, J. 



Q. J. G. S. No. 184. 2 s 



