WHITEAVES.] DEVONIAN FOSSILS OF MANITOBA, KTC. 339 



Point (two specimens), also at two exposures, one alnrnt two miles west of 

 Salt Point (tw(j specimens), and the other at the mouth of the Red Deer 

 River (where it appears to )je abundant) ; J. B. Tyrrell, 18S9. 



Most oi the specimens from these localities are either imperfect casts 

 of the interior of the shell, with well presei\ed poi'tions of the tests 

 attached, (jr sharply defined moulds of the exterior, in dolouiite. Only 

 two or three testiferous specimens were obtained and these are very 

 iuiperfect. The surface mai'kings are very \'aria)jle, not only in diffei'ent 

 specimens, but sometimes also in different parts of the same shell. Thus, 

 on the outer ^(:llution of (ine of the specimens from the small island north 

 of Salt Point, (tig. o) the markings consist of slightly siginoidal, acute 

 ridges, from two to three millimetres apart, with tine stri:e between them 

 and parallel to them. On the other hand, in the original of tig. 4, which 

 is drawn from a wax impression of a natural mould of a specimen from 

 the mouth of the Red Deer Pvi\er, the crowded subsigmoidal growth lines 

 or minute costuhe a.i'e very nearly equal in size and not more than from 

 one-half to a whole millimetre apart. In another specimen from the mouth 

 of the Red Deer River the sigmoidal costuhe on the last whorl but one 

 are nearly a millimeti'e apart, with finer stri;e between them, but they 

 suddenly become nearly equal in size and much closer together on the outer 

 volution. The entire height of one of the largest specimens from Dawson 

 Bay would probably have been about sixty millimetres. 



It is still doubtful whethei' the distinction between M. snhcosfctta and 

 J/, arculatii can be sustained. The characters which Mr. Whidborne, the 

 most recent writer on the subject, (op. cit., pp. 159-63) seems to rely upon 

 for separating English or German examples of the two forms are, the pro- 

 portionately narrower and shorter body whorl of J/, (irciiluld, its " flat, 

 angulated shoulder," and finer and more irregular surface markings. Yet' 

 Mr. Whidborne includes in the synonymy of 21. arculata, the specimen 

 figured under the name JLicrocIn'ihis arcu/ndis by Ferdinand Roemer, on 

 Plate xxxii. (fig. 6) of the '' Leth(eapal;eozoica,' in which no such shoulder 

 is apparent, and the Chudleigh specimens of 21. (U-cnlata, which he him- 

 self figures, are all equally shoulderless. Fischer's figure of Macrocldhn^ 

 ru'i:i(/iitus,* which is not referred to by Mi-. "Whidborne, is almost a fac- 

 simile of F. Roemer's, and the present writer has failed to understand how 

 the specimens of 2J. nn-ulafiis figured by F. Roemer, Fischer, or Freeh, | 

 can be distinguished from the specimen of J/. KiilirostulK figured by 

 d'Archiac and de Verneuil under the name J/. Sc/ilof/ieimli. Still, if 

 these two names are to be retained, the Dawson Bay specimens undoubt- 



*Man. de Conchyliologie, &c., ISSr,, p. U98. 



tUeb. das Devon der Ostalpen, pt. 2, (Zeitsohr. der Ueutsch. geolog. Gesellfloh., 

 1891) p. 679, pi. xliv, fig. 5. 



