'J to 



shows a distinct revolving- band formed by 

 the backward bending of the lines of growth 

 near the snture, the lip thus having a deep 

 emargination or sinns, as in Plenrotoniaria ; 

 the early stages of the shell are typical of 

 the species ; surface reticulate by re\'olving 

 8trifT crossed by the lines of growth. 



Found associated with Stictopora and 

 Spirorbis, in the Demissa (?) bed (one specimen 



Fig. 200 a. Platyos- 

 toma linenta, var. 

 emarginata. Summit 

 view. (Original.) 



Genus LOXONEMA. Phillips. 



[Ety. : Loxos, oblique ; nema, thread.] 

 (1841 : Pal. Foss. Cornwall, etc., p. 98.) 



Shell elongate, with a tall spire composed of many whorls. 

 The aperture is simple, narrow above, ample below. The 

 lines of growth are doubly curved, and there 

 is no umbilicus. 



LOXOXKMA HAMILTONLK. Hall. (Fig. 201.) 



(Pal. N. Y., Vol. v., Pt. II.. p. 45, PL XIII.) 



Distinguishing Chnracters. — Large number 

 (about thirteen) of volutions, gradually 

 increasing in size; ventricose body-whorl; 

 ovate apertui-e, narrowing l^elow ; distant 

 curving stride, which bend gently backAvard 

 from the suture, and forward from the l)ase 

 of the volution, with the greatest curve in the middle 



Found * * * " at Eighteen Mile Creek " 

 * * * (Hall), in the Strophalosia bed 

 wherever exposed (common). 



LoXONEMA DELPHICOLA. Hall. (Fig. 



202.) (Pal. N. Y., Vol. Y., Pt. II., p. 47, 

 Pis. XIII., XIY.) 



Distinguisliing Char act e rs . — Sm aller 

 number of volutions than preceding (about 

 eight); flattening of whorls; strong striai^, 

 bent slightly back for a short distance J^t-clla (afterTair 



Fig. 201. Loxone- 

 nia hamiUonioi (af- 

 ter Hall). 



