216 MISS J. DONALD ON THE GENUS [May 1 8 95 



sulcifera, Portl., and T. tceniata, Phill., which are doubtfully referred 

 to Murchisonia, there are thirty-seven Carboniferous species and one 

 variety (M. turriculata, var. scotica) referable to this genus. I have 

 not reckoned Worthenia tabulate/, amongst them, as it is probably 

 more closely allied to Pleurotomaria than to Murchisonia. 



In a former paper 1 I pointed out how much confusion has arisen 

 with regard to the identification of M. angulata of Phillips, as he 

 has described three different shells under this one name, two 

 Carboniferous and one Devonian. The type of only one of the 

 former is in existence in the Gilbertson Collection in the British 

 Museum (Natural History) ; it is a mere fragment, and very badly 

 preserved, and M'Coy has since described and figured better speci- 

 mens of the same form as M. Tcendalensis. Associated with this 

 fossil in the same collection is a portion of a tricarinate shell which 

 I thought might possibly be identical with the other Carboniferous 

 fossil figured by Phillips, but it is clearly not the actual specimen. 

 I then suggested that the name angulata might be retained for this 

 shell, but it seems better to abandon the name for a Carboniferous 

 species, more especially as E. Koken 2 considers the Devonian 

 Turbinites angulatus of Schlotheim 3 to be a Murchisonia. It is 

 not figured, and I have not bad the opportunity of examining the 

 original shell myself ; but, if Koken's surmise be correct, this form 

 has the priority, and must be taken as the type of M. angulata. 

 I therefore propose the name Gilbertsoni for the shell described in 

 Quart. Journ. Geol. Soc. vol. xliii. (1 887) p. 621, pi. xxiv. figs. 1, 2. 



The whole of the forms here enumerated may not ultimately be 

 considered distinct species; moreover some whose mouth and lines 

 of growth have not been clearly discerned may prove to belong to 

 the genus Aclisina, but these points can be decided only by the dis- 

 covery of more numerous and better-preserved examples. 



Distribution of the Species in the different Sections. 



The species may be thus disposed in the different sections : — In 

 Murchisonia, sensu stricto — cincta, clispar, dalryensis, fusiformis, 

 Gilbertsoni, hibernica, Tcendalensis, Larcomi, Marri, pyramidata , 

 ? sulcifera, subtilistriata, Tatei, tenuissima, Thomsoni, turriculata, 

 turriculata var. scotica, Verneuiliana, and Youngiana. These all 

 agree in having the sinual band on the angle or widest part of the 

 whorl ; in most it is similar to the type, being excavated and 

 bounded by keels. In four, dispar, Gilbertsoni, pyramidata, and 

 subtilistriata, it is not excavated, but is formed by a strong, pro- 

 minent keel, with occasionally a fine line on each side. It is a 

 question whether these should not be grouped in a separate section. 

 M. Tcendalensis has the band on the higher whorls excavated and 



1 ' Notes upon some Carb. Sp. of Murchisonia in our Public Museums,' Quart. 

 Journ. Geol. Soc. vol. xliii. (1887) p. 621. 



2 ' Ueber die Entwicklung der Gastropoden vom Cambrium bis zur Trias ' 

 Neues Jahrb. Beilage-Band vi. (1889) p. 369. 



3 ' Die Petrefactenkunde,' Gotba, 1820, p. 164. 



