CANADIAN FOSSILS. 31 



L. MuEEAYANA, N. Sp. 



Plate VI. Figure 6. 



L. 2| uncias lowga, anfractibus regulariter convexis etiam infiatis, ne 

 supra planulatis, (ad suturam vallo angusto notatis,) striis concentricis 

 obscuris, striis inc?"ementi conspicuis, antrorsum arcuatis : umbilico 

 nullo; ore obovato. 



The length of this species must have been full two and a half 

 inches, and the diameter of the lower whorl not less than three 

 quarters of an inch. The whorls are very convex, almost inflated, and 

 have no special prominence in any part ; their base is a little produced. 

 The sutural edge is a fine raised thread, and beneath it occurs a 

 narrow flattened space (with a raised border on the lowest whorl). 

 There are a few faint concentric striae, but the lines of growth are 

 the only prominent ones ; they are strong, sigmoid, the backward 

 curve short, the lower forward one a broad arch, reaching further 

 forward than their origin at the suture. There is only a minute 

 umbilical depression, with no bounding ridge, and the inner lip is 

 incomplete, its edge simple, not reflected. 



A single specimen only has occurred of this fine shell, and I have 

 pleasure in naming it after Mr. Alexander Murray, who has labored 

 so long in the Canadian Survey. 



Locality. — Pauquette's Rapids. Murchisonia (Loxonema ?) subfusi- 

 crmis, Hall, appears also to occur in this limestone. 



Cyetoceeas, Goldfuss. 



Generic characters. — Cyrtoceras, Goldfuss. Shell curved or partially 

 involute, sometimes with the transverse, at others the longitu- 

 dinal, diameter the greater. Aperture often contracted (in the 

 smooth forms). Siphuncle subinternal, central, or external. 

 (Barrande.) 



Section Cyrtoceras. — Curved ; siphuncle variable in position, simple, 



Gyroceras. — Involute ; siphon internal or subcentral, solid, 



radiated. 



It is not easy, in the absence of a perfect structure in the siphuncle, 

 to separate Cyrtoceras from Gyroceras, the principal difference being 

 the more regularly involute form and ornamented surface in the 

 latter (just as in the case of Toxoceras and Crioceras among the 

 genera with foliated septa). 



