.■'ilfi COXTlUBU'riONS TO CAXAIIIAN PAr^ECIN'TOLOCV 



ditt'eient Carbunifernus shells as Run/cf/arid aiigulata : and in 1S41, in the 

 'Pal. Foss. of Devon,' p. 101, pi. xxxix, Hg. 189, he figures and describes 

 a Devcjnian shell as Miirchlnnnia mu/iili4a, identifying it with the shells 

 previously described as Ronli'lJaria nmjulata, and referring them all to the 

 genus Miurhif:onia, d'Arch. and de Vern. This last shell is e\-idently 

 quite distinct from those first described, being much smaller, and the 

 keels differently disposed ; the only point of resemblance being that both 

 it and the shell figured on the right hand of pi. ' xvi (not xii),' fig. 16, 

 in the 'Geol. Yorks,' are tricarinate." After discussing the relations of 

 the British Carboniferous species of J/ii.rchiscmia to Phillips's M. <ingu/ata, 

 she goes on to say : " A. d'Archiac and E. de Verneuil and Goldfuss 

 ha\e referred Devonian shells to this species. That of the former differs 

 from Ijoth of Phillips's figures ; the more rapid increase of the whorls, and 

 the absence of the keels below the band, distinguish it from the right- 

 liand figure, while the whorls are more excavated than those of the left- 

 hand figure. The shell described by Goldfuss, which I have examined in 

 the Bonn Museum, increases more I'apidly ; the V^and is formed of two 

 keels placed close together and the whorls are more excavated." Koken,* 

 also, states that the Miirii:iti's (i.iujiihitun of Schlotheim (18:22) is a Mtir- 

 cJi'isd'iiia, but that it is quite different to the A/arc/dsonia arupiJata of 

 d'Archiac and de Verneuil. 



Under these circumstances, a new name seems to be reijuired for the 

 species now under consideration, and as L. G. de Koninck has already 

 gi\"en that of M. de Verneuil to a Carboniferous species, it may not be in- 

 appropriate to dedicate this to the memory of his fellow-labourer, the 

 \'iscount d'Archiac. 



(S.) MUIK.'IIISONIA Do\VLIN(;iI. (N. >Sp.) 



Plate 41, fig. 8. 



Shell elongated, turreted, very slender and many whorled. Volutions 

 thirteen or mor'e, the first three or four rounded or indistinctly angulated, 

 the remainder strongly angulated and distinctly bicarinated considerably 

 below theii' midlength, the two prominent spiral keels being placed close 

 t<igetlier and separated by .i narrow but rather deep groove, and the 

 centre of the basal or anterior side of the upper keel encircled by an im- 

 pi-essed line : sides of the volutions oVjliquely flattened and somewhat 

 conca\e both above and below the two spiral keels, but narrowing much 

 iiioi-e abruptly inward below them ; suture deeply and angularly ex- 

 ca\ ated, its centre occupied by a very fine but deeply impressed line oi' 

 minute spiral groove. 



^' I^flxT die J2ntvvickel, flnr (xaHtrop. voui Cambrian bis zur Trias. Separat-Abdr. 

 aus dfiu NfiiHU Jahrbuuh fur Mineralofrie, 1889, Beilageband \'i. 



