194 Prof. F. M'Coy on some new Lower Palaozoic Mollusca. 



one forming the circumference of the basal whorl^ and par- 

 tially concealed by the suture in the spiral whorls ; base con- 

 vex, with three smaller spiral carinse and a minute umbilicus ; 

 surface crossed by sharp, scaly, delicate, transverse striae. 

 Width 1 inch, proportional length about j^q, length of last 

 whorl tVo- 



Col. Portlock has, I think, figured this species (Geol. Rep. 

 t. 30. fig. 3) as the E. subsulcatus of Hisinger, which has double 

 the number of spiral keels on the upper surface. I should have 

 referred those specimens to the E. cornu-arietis (His.), but that 

 seems to have four large ridges to each whorl, and no indication 

 is given in the figure or description of the spiral carinse on the 

 base. It much resembles some of the varieties of the Pleuroto- 

 maria umbilicata (Hall) from the Bird^s-eye limestone of New 

 York, but is certainly distinguished by its smaller umbilicus, and 

 the three additional spiral keels on the base ; those latter are ge- 

 nerally best seen in the concavity left when the upper whorls of 

 a specimen are broken away (described from internal casts) . 



Common in the Bala slates of Cyrn-y-Brain, Wrexham, Den- 

 bighshire ; and in the schists of Golden grove, Llandeilo, Caer- 

 marthenshire. 



{Col. University of Cambridge.) 



Maclureia macromphala (M'Coy). 



Desc. Discoid, sinistral, usually elliptical, of about three and a 

 half rapidly enlarging whorls ; spire depressed below the level 

 of the outer turn, which bears an obscure, obtusely rounded 

 angulation, bounding the slightly oblique upper plane of the 

 shell ; circumference obtusely rounded ; under side having the 

 middle of the whorls obtusely angulated, thus defining a wide, 

 shallow umbilicus. Diameter 10 lines, proportional diameter 

 of last whorl ■^■^■^, height of last whorl -^^q, diameter of umbi- 

 licus y^Q^^. Surface crossed by minute, thread-like lines of 

 growth, extending obliquely backwards from the suture, and 

 then crossing almost directly into the umbilicus. 



This little species is easily distinguished from the M. magna 

 by its very wide umbilicus (resembling that of the carboniferous 

 Euomphalus pentangulatus), and by the more rapidly enlarging 

 whorls, which also separate it from the imperfectly known 

 M. matutina and M. sordida (Hall), from the calciferous sand- 

 stone of New York. 



In the concretionary and schistose limestone of Craig Head 

 near Girvan, Ayrshire. 



{Col. University of Cambridge.) I 



