310 



THE CARBONIFEROUS SYSTEM. 



Murchisonia gypsea, n. sp. (Fig. 123), coll. H. Poole, Windsor. — 

 Like M. nana, De Koninck, but larger, and with, only two revolving 

 ridges on the whorls. 

 Fig. 122. — Loxonema acutula, magnified. Fig 123 — Murchisonia gypsea (cast) 



Murchisonia tricingulata, n. sp., coll. J. W. D., Windsor, Pugwash. — 

 Resembles M. angulata, Phil., but has a keel above as well as below 

 the central band on the whorls. 



Pleurotomaria dispersa, n. sp., coll. H. Poole, and Hartt, Windsor. 

 — There are several small species of this genus. One, which is very 

 abundant in bed (6), Hartt, at Windsor, is that above named. It 

 has four flat whorls, giving it an almost regular conical form, with 

 delicate striae across the whorls. 



Pleurotomaria ignobilis, n. sp., coll. Hartt, Windsor — Almost exactly 

 of the form and markings of P. nobilis, De Koninck, with three re- 

 volving carina? ; but without the delicate sculpture between the carina. 



Cephalopoda. 

 Fig. 124. — Nautilus Avonensis. 



(a) Shell of small size. 



(b) Cross section. 



