ALLORISMA MAXIMA. 421 



Observations. — The type specimen of Sanguinolaria maxima, Portlock, is 

 fortunately preserved in the Museum of the Geological Survey at Jermyn Street, 

 and I am permitted to refigure it by the kindness of Sir A. Geikie^ PI. XLVII, 

 fig. 5. There can be no doubt that this fragment is the anterior part of the sliell 

 described afterwards by M'Coy {op. cit.) as SanguinoUtes clava, and therefore this 

 name must be discarded in favour of the earlier one. M'Coy seems to have noted 

 the resemblance between his shell and Portlock's species, for he states, " The only 

 approximation to this species published that I know is an indeterminate fragment 

 of one end of a shell called 8. maxima by Portlock, ' Geol. Rep.,' t. xxxvi, p. 11, 

 which is flatter, with smaller beaks, a more truncate anterior end, etc.," the 

 ** etc." not being more fully indicated. I have compared the type specimens, and 

 am unable to appreciate the differences described by M'Coy; but probably he was 

 basing his opinion on a not very perfect figure, and had not examined Portlock's 

 type. Owing to the fact that M' Coy's specimen was incomplete posteriorly, the 

 sinuated pallial line was not observed. The sinuatiou, though large in amount, is 

 very slightly indicated, especially with respect to its upper limb ; PI. XLVII, 

 fig. 7, a fine specimen, in the possession of Mr. J. G. Goodchild, F.G.S., shows 

 the pallial sinus very well indeed. 



I have been able to compare several specimens of the North-American shell, 

 A. subcimeata, with A. maxima; and, being unable to see any difference between 

 them, I have placed Meek and Worthen's name among the synonyms. Meek and 

 Worthen quite recognised the possibility of the two species being identical ; for in 

 their remarks on the species {pp. cit., 1865, p. 38) they say, " This species is 

 very closely allied to SanguinoUtes clava of M'Coy, and may possibly prove to be 

 identical when a direct comparison of specimens can be made. Those we have yet 

 seen of the Kansas fossil differ from M'Coy's figures in being straighter on the 

 dorsal margin, and more produced as well as more narrowly rounded in the 

 antero-ventral region. Their concentric undulations are also more obscure, and 

 the lunule-like depression in front of the beaks less distinctly defined in our shell." 

 M'Coy's figured specimen was very incomplete, the posterior fourth being 

 wanting, so that it would be impossible to postulate anything as to the dorsal 

 margin, its extent and character. I believe the difference in the character of the 

 concentric undulations is due to comparison of the external and internal casts of 

 the species. 



A. maxima is a very rare shell in British Carboniferous rocks, and of very 

 limited distribution. At present it has not been found in the Carboniferous rocks 

 of the Pennine system. The majority of the specimens, and all the perfect ones, 

 come from two localities in North Wales. Meek and Worthen obtained their 

 specimens from the coal-measures of Kansas, U.S.A. 



