81 



The name Stricldandici^^ was afterwards changed by me to StricUand- 

 inia, as it had been previously applied to a genus of fossil plants. (Can. 

 Nat. Geol., vol. 8, p. 370, October, 1863.) The species cited above as 

 p. Jccvis, should have been quoted as " S])lr'iferf IceviSj'^^ figured by J. de C. 

 Sowerby in the Silurian System," pi. xxi., fig. 12. At the time I 

 wrote (1859) this species was known in England not to be a Spirifer but 

 a Pentameriis, as that genus was then understood ; I therefore called it 

 P. IceviS' It is figured by Sowerby with a straight hinge line, sixteen 

 lines in length. That this is the species intended by me, is proved by the 

 following remark on p. 84, vol. 1, of this work (in the part issued in 

 1862.) It is there stated of Stricldandinia, that: — " The hinge line in 

 some of the species, such as in S- Iccvis and S- mocrocamerus, have the 

 hinge line straight and much extended." This sentence is irregular, but 

 as its meaning is obvious I make no alteration in it. It proves clearly 

 that the species intended by me had a long straight hinge Hne ; and could 

 not, therefore, have been P. l(Evis, of James Sowerby, 1813, the young of 

 P. ohIonrjHS, as represented by Mr. Davidson and Prof. Hall, in the works 

 cited below. -'"^ My generic description rigidly excludes P. oUongnSy 

 whether young or old. There is no resemblance whatever, between the 

 young of P. ohhngus (as figured by J. Sowerby) and any species of 

 Strkklandinia yet described. 



Stricklanlinia canadensis. (Billings.) 1859. 



PL 6, fig. 3, and pi. 7, fig. 2. 

 Stricklaxdia canadensis. (Billings.) Canadian Nat. and Geol., vol. 4, p. 135, 1859. 



Bescription, — Shell large, sub-circular or transversely broad-ovate, 

 compressed or sub-lenticular ; surface, as indicated by the casts of the 

 interior, covered with convex radiating ribs, and concentric step-like, 

 sub-lamellose rings of growth. 



The ventral valve is moderately convex, most elevated in the upper 

 half or third of the length, usually strongly compressed or sub-concave 

 towards the sides, especially in the upper two-thirds. A mesial sinus 

 commences on the umbo, and gradually widens to the front margin, where, 

 in large specimens, it is sometimes an inch or more in width. It is 

 generally shallow and concave, and though always perceptible, is some- 

 times very slightly indicated. The dorsal valve seems to be of about the 

 same convexity as the ventral, and has an obscure mesial fold correspond- 

 ing to the ventral sinus. 



* Davidson'; "British Fossil Bracbiopoda," vol. 3, p. 158. Hall; Pal., N.Y., vol, 4, p. 

 370. 



