345 



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

 this species should be called an Opldleta, a Helicotoma, or an Ecculiom- 

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



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

 ous formation. 



Collector. — E. Billin'ji;s. 



MURCHISONIA ArTEMESIA. (N. Sp.) 



Fig. 332. 



Fig. Z32.—Murclmonia.irtemcsia. a, cast of the interior of a fragment of this species ; 

 b, a specimen partly restored. 



Description.— ^\xe\\ 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 sutul-e. The casts of the exterior show a strong 

 rounded band along the median line of the Avhorls : it is about one Hne 

 wide on the large whorls. Surface with fine sharp striae 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 difiers from M. simulatrix (ante, p. 231, 

 fig. 218). Jf. affilis (ante, p. 235) has the suture not so oblique. 

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



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

 erous formation. 



Collector. — E. Billings. 



X 



