Pahrozoic Bivalved Entomostraca. 845 



1873. Genus, Schmidt, Mt^m. Acad. Imp. Sci. St.-Petersb. s^r. 7, 



vol. xxi. no. 2, pp. 9, 21. 

 1881. Genus, Jones, Ann. & Mag. Nat. Hist. ser. 5, vol. viii. p. 346, 



vol. ix. p. 171. 



Isochilina Ottawa, Jones. 



Leperditia (Isochilina) Ottawa, Jones, Ann. Jk Mag. Nat. Hist. 1858, 

 ser. 3, vol. i. p. 248, pi. x. fig. 1 ; Geol. Surv. Canada, dec. iii. 1858, 

 p. 97, pi. ix. tig. 14. 



Specimens in the McGill University Museum. Lahelled 

 " 595." "■ Leperditia, 5 miles west of L'Orignal." Chazj 

 Limestone. 



This is Isochilina Ottawa, Jones ; in dark grey limestone 

 composed of these tests. Some are shorter and higher than 

 others. The eye-spot is feebly marked in general, but stronger 

 in some individuals. The valves vary from -j- inch in length 

 to \ long and js high and i long and ^ high. 



Isochilina Ottawa was first got from the Chazy Limestone 

 at L'Orignal and from the Calciferous Sandrock at G-ranville. 



" 881." On this large slab of Zs-ocA^V^'/ia-Limestone the 

 Isocliilina Ottawa is larger (| inch long), with stronger eye- 

 spot and with a feeble muscle-spot. 



Genus Primitia, Jones and Holl, Ann. & Mag. Nat. Hist. 

 1865, ser. 3, vol. xvi. p. 415. 



Beyrichice simplices, Jones, Ann, & Mag. Nat. Hist. 1855, ser. 2, vol. xvi. 

 p. 85. 



Primitia leper ditioides, Jones. 



Beyrichia Loyani, .Tones, var. leper ditioides, Jones, Ann. & Mag. Nat. 



Hist. 1858, ser. 3, vol. i. p. 244, pi. ix. tig. 10; Geol. Surv. Canada, 



dec. iii. 1858, p. 91, pi. xi. figs. 1-5. 

 Primitia Loyani, Jones, var. leperditioides, Jones, Ann. & Mag. Nat. 



Hist. 1865, ser. 3, vol. xv. p. 416. 



In the McGill University Museum. Labelled "635." 

 ^^ Leperditia, Trenton (B. R.), Pointe Claire." 



Small black carapaces and valves in a dark grey limestone 

 with ferruginous bed-plane and some marly seams. The 

 limestone is largely composed of these tests, with Polyzoa &c. 

 This is not a Leperditia, but Primitia Logani, Jones, var. 

 leper ditioides, Jones, or, preferably, P. leperditioides, Jones. 



It is yV inch long, -^^ inch high. 



P. leperditioides was originally obtained from tlic " Calci- 

 ferous Sandrock " of Grenville. 



