23? 



that the outline of a transverse section through the centre of the valves 

 would be subtriangular, the two upper sides being somewhat convex 

 and the base shallowly concave : maximum thickness, as measured 

 from keel to keel, a little greater than the height. Lateral outline 

 narrowly mytiloid, valves slightly curved and much elongated trans- 

 versely : anterior end acutely pointed : J posterior obtuse : superior 

 border broadly arched but not very prominent : basal margin shallowly 

 concave : beaks anterior, terminal and approximated. Surface appar- 

 ently marked by coarse concentric striae of growth, with finer stria> 

 intercalated between them. 



Length of the only specimen collected, fifty-six millimetres : height, 

 as measured from the lateral keel to the centre of the hinge line, 

 eighteen mm. : greatest thickness, from keel to keel, twenty-two mm. 



Shingle Eay, Skidegate Inlet : a cast of both valves with a very 

 small piece of the test preserved. 



The above is a purely original description of the specimen collected 

 by Dr. Dawson, from which it. may be seen that its characters do not 

 seem to differ in any essential particular from those of the M. lanceo- 

 latus of Sowerby as described by d'Orbigny, Pictet and other palaeon- 

 tologists. 



MODIOLA SUBIMBRICATA, Meek. 



Modiola ( Vo(sella) subimbricata, Meek. 1873. Annual Report of the United 



# States Geological Survey of the 



Territories for 1872, p. 472. 



" (Sp. undt) This volume p. 73. 



Volsella suUmbricata, White. 1880. United States Geological Sur- 



vey. Contributions to Palaeonto- 

 logy, Nos. 2-8, p. 145, pi. 37, figs. 

 2a b, &c. 



East end of Maud Island : three distorted specimens, two of which, 

 however, have the test preserved on both valves. 



LITHODOMUS MAUDENSIS. (N\ Sp.) 

 Plate 32, figs. 6 and 6a. 



Shell convex, the maximum thickness through the closed valves being 

 about equal to their greatest height, most prominent laterally, in the 

 direction of a curved line which might be drawn from the under side 

 of the beaks to the posterior end of the base, beneath and in front of 



