345 



of tlie whorls is about equal to their width. It is difficult to say whether 

 this species should be called an OpMleta, a Relicotoma, or an JEccuKom- 

 phalus. These genera seem all to run into each other. 



Locality and Formation. — Counties of Leeds and Grenville ; Calcifer- 

 ous formation. 



Collector. — E. Bilhngs. - 



MURCHISONIA ArTEMESIA. (N. Sp.) 



Fig. 332. 



Fig. 332. — Murchisonia Jlrtemcsia. a, cast of the interior of a fragment of this species ; 

 6, a specimen partly restored. 



Description. — Shell elongate, slender with from ten to twelve depressed 

 convex whorls and a strong rounded spiral band. The whorls, in the 

 cast are depressed ventricose, flattened in the middle and abruptly 

 rounded into the deep suture. The casts of the exterior show a strong 

 rounded band along the median hne of the whorls : it is about one line 

 wide on the large whorls. Surface with fine sharp strias curving back- 

 wards to the band. 



Length from 2i to 3 inches ; apical angle about 15°. 



Resembles M. gracilis, but is always more elongate and with flatter 

 whorls, in which respects also it differs from M. simulatrix (^ante, p. 231, 

 fig. 218). M. agilis (^ante, p. 235) has the suture not so oblique. 

 31. vesta (ante, p. 32) is a shorter and more abruptly tapering form. 



Locality and Formation. — Counties of Leeds and Grenville ; Calcif- 

 erous formation. 



Collector. — E. Billings. 



