80 CANADIAN MICRO-PAL.T.ONTOLOGY. 



There are two other loose specimens from harder cream-coloured lime- 

 stone at the north end of Mossy Portage, Cedar Lake, collected by Mr- 

 Tyrrell in 1890. These latter have the test preserved, but resembling 

 the matrix. 



The drawings of these specimens from the white limestone have 

 been made from trustworthy plaster-casts of the natural hollow im- 

 pressions (moulds) of the outsides of the valves, the artist having, also, 

 the original specimens before him. 



Specimens Nos. 1-6, from the east side of Lake Winnipegosis. 



Specimen No- 1 — Hollow mould of a right valve. The plaster-cast is figured 



(fig- 1)- 



No. 2 — Hollow mould of a left valve (not figured), rather yellowish. 



' No. 3— Hollow^ mould of a right valve. The plaster-cast is figured 



(fig- 2). 



No. 4 a — Hollow mould of a left valve ; ocular tubercle strong ; muscle- 

 spot and radii visible. 



No. 4 b — Convex left valve. Test attenuated probably by solution. 



No. 5 — Convex left valve. Test present; muscle-spot good. 



No. 6 — Hollow mould of a left valve ; like No. 3. Muscle-spot figured 



(fig. 3). 



Specimens Nos. 7-8, from the north end of Mossy Portage, Cedar Lake. 



Sjjecimen No. 7 — Convex right valve, attenuated by solution. Muscle-spot 

 figured (fig. 4). 



No. 8 — Convex left valve, attenuated by solution. 



This species has been found also as follows : A small specimen, not 

 well exposed, about 7 mm. long, in a hard, rough, buff-coloured lime- 

 stone, at Cross Lake Rapids (at the eastern exit of the lake), on the 

 Saskatchewan Eiver, east of Cedar Lake. G-eological position a little 

 above that of the Roche Rouge. Three specimens, with some Leper- 

 difice {L. Hisingeri, var-, and L. coecd) and many moUusca, in a white, 

 hard, thin-bedded limestone from the Grand Rapids below Old Portage, 

 near the mouth of the Saskatchewan. All collected by Mr. Tyi-rell in 

 1890. 



8. Leperditia balthica (Hisinger). var. guelphica, Nov. 

 PI. 1^, figs. 12 a, b, 13 a, b, c. 



Cylherina balthica (part), Hisinger. Anteckningar, Piiys. och Geogn, etc., vol. V, 



1831, pp. 109, 132, pi. viii, fig. 2 ; Lethsea Suecica, 1837, p. 



10, pi. i, fig. 2. 

 Leperditia balthica (part), Jones. Ann. Mag. Nat. Hist., ser. 2, vol. XVII, 1856, p. 



85, pi. vi, figs., 12, 4, and 5. 

 Leperditia baltica, var. a. Kolmodin. Bidrag till Kannedomen om Sverges Silu- 



riska Ostracoder, 1869, pp. 13, 14, figs. 1, 2, and 3. 



