WHiTEAVEs] DEVONIAN FOSSILS OP MANITOBA, ETC. 337 



The figure on Plate xliv is taken fi'om a wax impression of the d<5rsal 

 surface of the last four volutions of an appaiently adult specimen, with 

 the earlier volutions restored from a gutta percha impression of another 

 specimen in which these happen to be well jireserved. 



The maximum breadth of the outer volution of the largest specimen 

 ccillected is twenty four millimetres, and the <'ntire height or length of an 

 adult specimen is estimated to have been about I'ighty five mm. 



Lake ^Manitoba, at Point Pichard, and Monroe Point, J. B. Tyrrell and 

 J. F. Wliitea\cs, ISSS; one specimen at each of these localities. Dawson 

 Bay, Lake Winnepegosis, at Whiteaves Point (four specimens), on n 

 small island about half way between that point and Salt Point (one spe- 

 cimen), and at the south end of Rowan Island (one specimen) ; J. B. 

 Tyrrell and D. B. r>owling, 1889. All the specimens are mere natural 

 moulds of the exterior of the shell, in dolomite, but in some tin; corres- 

 ponding cast <if the interior of the shell also is ])res('i'ved. 



The prominent, spiral ridges of this shell, which resemble those of some 

 of the recent and tropical iMelanias from the Pacific or eastern hemi- 

 sphere, will at once enable it to be distinguished from any other species 

 of Lii.roiieniK. 



Lo.XONEMA fiEACILLIMUM. (N. Sp.) 

 Plate 45, fig. 10. 



Shell verv small, narrowly elongated, slender, turriculated and many 

 whorled. Volutions about nine, increasing vi'i-y slowly in size, tlie earlier 

 ones of the spire moderately convex, the later ones ventricose in the mid- 

 dle and ))elow (or antei'iorly), but narrowly and concavely constricted next 

 to the suture abo\'e, a little l)roadpr than iiigh . outer volution apparently 

 coi\siderably higher but not very much broader than the one which imme- 

 diatelv precedps it, though the basal portion and the characters of the 

 aperture are unknown : suture distinctly defined. 



Sui-face (of the lowei- volutions) marked with spiral revohing ridges, 

 which aie crossed b\' numerous and \'ery minute sii;moidal costuhe, or 

 simple and entire thread-like raised lines. In tlie oidy specimen collected, 

 which is imperfect at the base, nine spiral or ri'\-olving ridges can be 

 counted on the last volution, and six on the last lait one. These ridges, 

 most of which are large cnouijh to be seen with the nak(;d eye, are une(|ual 

 in size, four of those on the most pronjinent and 1ow(M- i>art of the two latest 

 volutions being larger and more elevati'd than the others, and all of them 

 are narrow and minutely tuberculated at th(; many points where the sig- 

 moidal costuhe pass over them. The sigmoidal costuhe, which cross the 



