326 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



EUOMPHALUS (CIRCULARIS? Phillips, var.) SUliTBIGONALIS. 

 Plate 43, fig. 4. 



Cfr. Eiioiiiphiilus circnbiris, \m: Wbidbonip. IS'.ll. Muii. Pev. Fauna ,S. England, p. 

 249, v(il. I, ]>1. xxiv, tigs. I) and 9a. 



Shell, Of nithei- cast of th(> interior of the shell, depressed turljiiiate, 

 almost diseoidal : spire low, in the majority of specimens raised very 

 little aljove, Ijut occasionally depressed Ijelow, the highest level of the 

 outer volution : Ijase obliquely and concavely excavated, as well as widely 

 umbilicated. A^jlutions about four, though the apex is not presei-ved in 

 any of the specimens collected, those of the spire depressed convex, the 

 outer one widely expanded, more than twice as broad as high, sub- 

 triangular in transverse .section, flattened above, laterally compressed on 

 the peripher-y, subangular at the shoulder above and around the umbilical 

 margin below : umbilicus wide but shallow, exposing the basal side of 

 each of the inner volutions : suture channeled and distinctly defined : 

 aperture ovately subtriangular, narrow and obtusely pointed at the base 

 below. 



Surface markings unknown, not a vestige of the test being preserved 

 on any of the specimens collected, which are all mere casts. 



It is not practicable to give very accurate proportional dimensions of 

 any (if these casts, but the tigure on plate xlvii. is of the natural size. 



Onion Point, Lake Manitoba, J. B. Tyi-rell and J. F. Whiteave.s, 1888 : 

 four specimens. Lake Winnipegosis, at its southern extremity, on 

 Charlie and 8nake Islands, and at two exposures on the adjacent shore, 

 also in Dawson Bay, on Beardy Island and at Point AVilkins, J. B. 

 Tyrrell, 1889 ; from one to six .specimens at each of the.se localities. All 

 from the limestone immediately overlying the Stringocephalus zone. 



The precise specific relations of these specimens must remain doubtful 

 until examples with at least some portion of the test preserved are col- 

 lected. In the meantime all that can be said .about these casts is that 

 they correspond very well with the description of " decorticated " speci- 

 mens of one of the varieties of th(^ Euoiii.j}}i,ahi,s i-.irinihiris of Phillips 

 figured in the monogragh cited above. They are also somewhat similar 

 in shape to the E. trii/onalin, of Goldfuss, but the outer volution of each 

 is not nearly so sharply angulated either above or below, and their apertures, 

 in consequence, ai-e not so distinctly triangular in outline. 



