Vol. 51.] MUECHISONIA AND ITS ALLIES. 215 



M'Coy describes two different forms as M. sulcata : the first in 

 1844 in the ' Synops. Char. Carb. Lste. Foss. Ireland,' p. 42, pi. v. 

 fig. 10, which is quite distinct from that described in 1862 in the 

 ' Synops. Sil. Foss. Ireland,' p. 17, pi. i. fig. 20. The type of the 

 former ought to be in the Museum of Science and Art, Dublin, 

 where the Silurian species is, but it cannot be found there. In the 

 ' Brit. Pal. Rocks,' p. 532, M'Coy refers to M. sulcata some small 

 shells in the Woodwardian Museum, Cambridge, from Craige, 

 Kilmarnock. Both the figure of the type and these last-named 

 shells are too short to be included with Murchisonia, therefore this 

 species cannot be reckoned as a member of that genus. 



In the following pages I am about to show that M. Humboldtiana, 

 De Kon., is most probably identical with Pleurotomaria fusiformis, 

 Phill. It is doubtful whether Turritella tceniata, Phill., is a true 

 Murchisonia, as the surface of the only specimen is so imperfectly 

 preserved that it does not give distinct evidence of the possession of 

 a sinus in the outer lip. It may be well, however, to retain it in 

 the genus Murchisonia, where it has been placed, until we meet 

 with sufficiently good specimens to prove its affinities. The type of 

 M. Larcomi, M'Coj 7 , has evidently been mislaid or lost, and the only 

 specimen in the Museum of Science and Art, Dublin, is so poor that 

 it is impossible to make out its characters ; therefore I cannot say 

 whether it may not be identical with a species since described. It 

 is difficult to determine these small shells satisfactorily from figures, 

 unless they are very accurately drawn. Thus six species must be 

 deducted from the list, but three previously described shells may be 

 added. M. kendalensis, M'Coy, was recorded by Bigsby in 1878 in 

 his ' Thes. Dev.-Carb.' p. 327. Cerithioides telescopium, Haughton, 

 is placed both by Bigsby (p. 319) and Etheridge (' Foss. Brit. Islands,' 

 vol. i. Palaeozoic, 1883, p. 295) among the Pyramidellidas, in which 

 family it was originally included by Prof. Haughton. I have since 

 shown that it possessed a sinus in the outer lip, represented on the 

 whorls by a spiral band ; it must therefore be classed with the 

 Murchisonia}. Turritella (?) suleifera, Portl., recorded both by 

 Bigsby (op. cit. p. 335) and Etheridge (op. cit. p. 308) in the Turri- 

 tellidae, is most probably a Murchisonia ; though neither mouth nor 

 lines of growth are preserved to indicate the possession of a sinus, 

 it bears a close resemblance to some of the small-keeled Murchisonice, 

 and it may indeed be identical with one of them, but the only known 

 specimen (the type) is too small and imperfect to admit of certainty 

 upon this point. 



There have since been described seventeen additional species and 

 varieties, viz., M. compacta, Don., conula, De Kon., var. convexa, 

 Don., hibemica, Don., Kirkbyi, Don., pyramidata, Don., pentonensis, 

 Don., plana, Don., quinquecarinata, De Kon., var. pulchella, Don., 

 sph&rulata, Don., suhtilistriata, Don., tenuissima, Don., turriculata, 

 De Kon., turriculata, var. scotica, Don., Tatei, Don., tuedia, Don., 

 ■ Verneuiliana, De Kon., and zonata, Don. Besides these I am 

 describing in the present paper eleven new species. Thus we have 

 a total of forty Carboniferous forms, or if we exclude Turritella (?) 



