CANADIAN FOSSILS. 3? 



in print, I wish to apply it to this fine species. Professor Hall has 

 figured it under the name dubia, but the figures given in his 

 Palaeontology of New York, plate 34, shew that species to have been 

 smaller and wider, the " length almost twice the height." It is 

 much more gibbous too, according to his figures, the edge being 

 turned quite abruptly inward. Mr. Billings, who has seen specimens 

 of the C. dubia, assures me they are distinct. 

 Locality. — With the last. Eare. 



C. CONTRACTA. 



Plate VIII. Figures 4, 5. 



C.parmda, tres partes uncice lata, trigomda, subaquilatera, antice rotundata, 

 postice cuneata carinata contracta, umbo?iibus elevatis prce medium 

 positis ; lunuld distinctd ; cardine dentibus majoribus. 



Synonym. — Tellinomya cuneata, Hall, Report, 1. c, figures 6, 7. 



A common but pretty little species, which well illustrates the 

 character of the genus as distinct from Nucida or Leda, to either of 

 which it bears a strong resemblance. Instead of two rows of teeth 

 separated by a spoon-shaped process to carry the ligament, the two 

 rows run into each other, with only a slight angular notch to 

 separate them, and the ligament is clearly seen outside, set on its 

 prominent fulcrum. 



The form is that of a wide triangle, with the gently elevated beak 

 rather nearer the anterior end. This is rounded into the ventral 

 border, which has its greatest convexity in advance of the line of the 

 beak. The shell too is most convex here, and a depressed line 

 separates the elevated and carinate siphonal ridge. The posterior 

 cardinal slope is flat in some specimens, and nearly so in all ; the 

 ligament fulcra marked out on it as a long oval lunette extending 

 half-way along it. A similar lunette, more deeply sunken, marks the 

 anterior side. The ligament itself is but small. 



Teeth about six or seven on each side ; beneath the beak a few 

 crowded ones occur ; they are straight, or nearly so, and set obliquely 

 inwards on both sides of the broad, bent hinge-plate. The beak 

 considerably overhangs the hinge (fig. 5a). 



The shell is thick, the impressions of the adductor muscles deep, 

 and close under the hinge-line. A small accessory scar occurs above 



