87 



glossy white, sinus broad and shallow, sutural laminae only 

 slightly produced. 



Girdle. — Under pocket lense appears whitish and felt-like. 

 The margined fringed with white spicules, but under one-inch 

 objective the girdle is seen to be crowded with masses of small 

 irregular imbricating scales, which are finely striated. 



Measurement. — Length, 26 mm.; breadth, 7 mm. 



Habitat. — St. Vincent's Gulf ; dredged by Dr. Verco. 



Remarks. — This species is much broader in proportion to its 

 length than juloides, the first valve being the broadest and very 

 rounded, the width being fairly maintained to the sixth valve 

 inclusive. Valves seven and eight taper rapidly, the latter being 

 almost pointed. It is also easily distinguishable from juloides 

 and Pilsbryanus by the anterior valve being longitudinally much 

 shorter, the creamy white colour, and the densely irregularly 

 scaled girdle. I am indebted to Dr. Verco for specimens of this 

 and the following species. 



Calloehiton rufus, sp. nov. PI. i., figs. 2a— g. 



General Appearance. — Shell oval, width three-fifths of total 

 length, carinated, side slopes very curved. Colour. — Uniformly 

 bright terra-cotta red, both shell and girdle, with the exception 

 of a small white spot on dorsal area of valves three to eight, and 

 the lateral area of valve seven, which is pure white; from this 

 valve a white line traverses the girdle; also the four first valves 

 have a light spot on the posterior margin. 



Anterior Valve. — Under pocket lense quite smooth, with the 

 exception of a few concentric growth lines. Megalospores are very 

 distinct under compound microscope. Slits 11, teeth crenulate, 

 which appearance is caused by the slight projection of the props. 

 The spongy character of the eaves is continued in the slits 

 between the teeth. 



Posterior Valve is almost equally divided into two areas, the 

 dorsal, or central, broadly wedge-shaped, traversed by eight 

 longitudinal strongly raised ribs, similar to those of the pleural 

 areas of the median valves. Mucro median, although shallow, 

 decidedly more prominent than in C. platessa. Posterior area 

 smooth, decidedly raised at the junction with the dorsal area. 

 Slight concentric growth lines are discernible. 



Median Valves. — Lateral area much raised, slight growth 

 lines ; also two or three shallow vertical sulci just distinguish- 

 able. * Densely pitted with megalospores, which are very distinct. 

 Pleural area longitudinally ribbed with scimitar-shaped riblets. 

 The pits between are very deep where they join the lateral area. 

 Dorsal area is raised, wedge-shape, divided from the pleural area 

 by a deep spindle-shaped pit, tapering off into a curved groove at 



