2 38 



curved inwards towards upper extremity. Orifice rather small and distinctly toothed. Longitudinal 

 rims furnished with small teeth, which in the younger specimens are more distinct and in the 

 older ones less distinct, extend from the upper extremity of the parietes downwards. Scutum very 

 broad, with short but strongly developed articular ridge. Tergum with the apex beaked, a broad 

 obliquely truncated spur, a deep longitudinal furrow, and the surface between the furrow and 

 the carinal margin beautifully decorated with crossing horizontal and longitudinal lines. Basis 

 conical, with the edge almost quite smooth. Fourth cirrus with rows of teeth along inner face 

 of pedicel and numerous segments of anterior ramus, fifth cirrus with similar teeth along inner 

 face of several segments of anterior ramus. 



This beautiful and very characteristic species (PI. XXIV, fig. 17) is coloured orange- 

 pink in the smaller and lighter pink in the larger specimens. The shape of the younger ones 

 is more globular, that of the older ones somewhat more elongate, the height of the capitulum 

 as a rule slightly surpassing that of the cup-formed basis. The upper parts of all the parietes 

 are curved inwards, and the tips enclose a moderate sized orifice of curious shape (PI. XXIV, 

 fig. 18). The outer surface of the parietes is — in the younger specimens — furnished with 

 small spinedike points arranged on longitudinal ribs and decreasing in number and size from 

 the upper extremity downwards. These ribs and the points disposed on them are much less 

 prominent in the older specimens. There are five of these ribs on the rostrum, four on the laterals, 

 three on the carina, while the carino-laterals have a series of such points along each longi- 

 tudinal side. For the rest, the outer surface is smooth, the inner surface being strongly ribbed 

 in longitudinal lines. These ribs on- the lower half are crossed by transverse ribs, the inner sur- 

 face having there a reticulated aspect. The radii are not very broad and du not extend down 

 to the basis; no apertures are left in the lower half, between the compartments. The summits 

 of the radii are very oblique, their edges are not crenated. The outer surface is feebly marked 

 by horizontal lines of growth and also by oblique lines running parallel to the lower half of 

 the lateral margin. The alae are about half the length of the parietes, they are slightly broader 

 than the radii, have more distinct horizontal lines of growth, and like the radii have very 

 oblique summits. 



The size of a large specimen was: total height 8.5 mm., height of the capitulum 

 5.5 mm., greatest basal diameter 6 mm. 



The scutum (PI. XXV, fig. 1, a and c) is relatively broacl and short: the occludent 

 and basal margins are long, the tergal margin relatively short. The occludent margin is almost 

 straight and only superficially toothed ; the basal margin is undulating, the lateral parts of the 

 outer surface being somewhat lifted up. The tergal margin is distinctly convex. Lines of growth 

 well-marked, longitudinal lines feebly indicated and only on the apical part of the valve. 

 Articular ridge short, broad, with rounded circumference, articular furrow deep. Cavity for the 

 musculi depressores indicated, but shallow. 



The tergum (PI. XXV, fig. 1, ö and d) is also broad, nearly as large as the scutum 

 and as strong or thick. lts carinal margin is curved, hence the angle it makes with the 

 feebly excavated scutal margin is somewhat produced : beakdike. The spur is short and broad, 

 more than one third of the width of the whole valve. lts base is truncated and extends parallel 



