226 



identical with the present species, the most perfect of which is repre- 

 sented by figure 3 of plate 30, were collected on the north side of 

 Maud Island. The specimens from this locality, which do not shew 

 any trace of the two surface markings, are smaller, less elongated 

 transversely in proportion to their height, and more nearly equilateral 

 than the types of T. Skidegatensis. 



CARYATIS STJBTRIGONA, Whiteaves. 



Callista (?) subtrigona, Whiteaves. 1876- This volume, p. 63, pi. 9, fig. 10. 

 Lucina. Sp. Undt " - " " " p. 61, fig. 6, and pi. 



9, fig. 12. 



(?) - " " " p. 62, fig. 7. 



Bear Skin Bay, Skidegate Inlet, extremely abundant : South side of 

 Alliford Bay, apparently not quite so common. 



The large series of specimens collected by Dr. Dawson prove conclu- 

 sively that the fossils doubtfully described on pages 61 and 62 of the 

 present volume as species of Lucina are really only distorted and 

 imperfect examples of Oaryatis subtrigona. 



THETIS APFINIS. (Nom. prov.) 

 Plate 30, figs- 4, 4a and 46. 



Probably a variety of Thetis major, Sowerby. 



Compare Thetis major, Sowerby. 1829. Mineral Conchology, Vol. 



VI., p. 20, pi. 513, figs. 1 to 4. 



Shell rather large (for the genus), moderately convex, the thickness 

 through the closed valves being about one-third less than the maximum 

 height ; outline variable ; in some specimens the lateral contour is 

 transversely ovate-orbicular, the ventral margin being more broadly 

 rounded than the anterior end, and the posterior end narrower and 

 a little longer than the anterior ; in others, which are very inequi- 

 lateral, the valves are ovately subtrigonal as viewed laterally, the 

 short anterior end being subangular at its junction with the superior 

 border above, and the produced posterior end obtusely pointed below 

 the middle. Umbones large and prominent : beaks curved inwards, 

 downwards, and a little forwards, subcentral in some specimens and 

 placed very near the anterior end in others. 



Surface marked with rather irregularly disposed concentric lines of 

 growth, and by a few very faint radiating stria'. 



Hinge teeth unknown. Muscular impressions transversely elongated 



