222 



margin. If a line be drawn between the most projecting points of the 

 anterior and posterior extremities, it will divide the shell into two nearly 

 equal parts : of these, the upper or dorsal half is triangidar, the umbones 

 forming the apex with an angle of about 120^, the posterior slope a little 

 longer than the anterior : the ventral half of the shell is semi-ovate, the 

 anterior end the largest. The shell is very thick, and rather strongly con- 

 vex. Surface with obscure concentric strise. Transverse length 8 lines ; 

 umbones to ventral margin 5 lines. 



Ctenodonta contrada (Salter) has the posterior extremity more pointed, 

 but in no other respect differs from this species. 



Locality and Formation. — M, Table Head, Newfoundland ; Quebec 

 group. 



Collector. — J. Richardson. 



GASTEROPODA. 

 HoLOPEA Ophelia. (N. sp.) 



Fig. 204. 

 Fig, 204. — Holopca Ophelia. Different views of the same specimen. 



Description. — Shell small, turbinate, apical angle between 80° and P0°; 

 whorls three, including a minute one at the apex, smoothly ventricose, 

 most prominent at about the lower third. Aperture sub-ovate, the outer 

 lip broadly convex, the inner lip, from the umbilicus down^vards, slightly 

 curved, and folded over the minute umbilicus ; the upper and inner half 

 of the aperture formed l)y the penultimate whorl . 



Length 6 lines ; width, IVom the outer lip through, about the same ; 

 height of the aperture, 4 lines. On a posterior view the two apical 

 whorls constitute only one-fifth the whole length. The last whorl forms 

 nearly the whole bulk. 



In some of the specimens there seems to be a spiral band about the mid- 

 dle of the whorl, as in Pleurotomaria. 



LocnUty and Formation. — L, Pohit Rich, Newfoundland ; Quebec 

 group. 



Collector. — J. Richardson. 



