i8 3 



with light rosé and red. Radii extremely narrow with oblique summits, alae narrow also and 

 with oblique summits. Scutum plainly striated longitudinally; tergum with the spur broad, 

 without a longitudinal furrow. 



This species in several respects resembles B. amaryllis, and belongs no doubt to the 

 same division of the genus. It is represented by two specimens. 



The general shape of the shell (PI. XVI, fig. 5) is conical, with the basal part, in the 

 larger specimen especially, rather swollen, and a relatively small and deeply toothed orifice. The 

 shell is slightly compressed laterally, in consequence of its being attached to a narrow and 

 rounded surface. The basis is hollowed out, with the concavity directed towards the object 

 (sponge ?) to which it is attached ; this basis is calcareous ; I could not make out if it has pores. 

 The compartments and radii have no pores. The radii are narrow, and have the summits very 

 oblique ; the alae are only slightly broader, they have the upper margins rounded and oblique. 

 The colour of the shell and radii is pale red, with darker and lighter longitudinal stripes, crossed 

 by a few horizontal and lighter-coloured bands. The alae are much lighter, almost of a white 

 colour. The larger specimen measures 1 1 mm. (greatest breadth at the basis), and has a height 

 of 9.5 mm. In the smaller specimen these measurements are 7 and 5.5 mm. respectively. 



Scutum and tergum in general appearance resembling very much the same parts in B. 

 amaryllis. The longitudinal striae on the scutum (PI. XVI, fig. 6, a and c) of the present species 

 are, however, still more distinct, hence the whole surface is divided into little squares in a more 

 prominent way. The inner surface of the scutum is coloured purplish-red, and is distinctly 

 furrowed longitudinally, especially in the basal part. The adductor ridge can be made out only 

 in the superior half of the valve, the articular ridge is narrow, and about half as long as 

 the tergal margin. 



The tergum (PI. XVI, fig. 6, b and d) has the scutal margin hollowed out, the apex 

 beaked. There is no longitudinal furrow. The spur is short, and cut off in an oblique direction. 

 lts length is a trifle longer than its distance from the basi-scutal angle. Crests for the depressor 

 muscles few and not very prominent. 



With regard to the structure of the animal's body, the following may be said : 



Mouth. Labrum (PI. XVI, fig. 7) with a rather deep notch, and three teeth situated 

 close together on each side of notch. The two margins of the labrum on each side of the 

 notch together make an angle; therefore the whole shape of the shield-like portion, is more 

 quadrate than triangular. The teeth are triangular, pointed at the extremity. 



Pal pi with the basal margin strongly arched, hence the whole shape is swollen as in 

 B. amaryllis. Numerous longer hairs are situated close together on a triangular portion of the 

 outer surface at the free upper corner. Hairs along upper margin numerous; those of the inner surface 

 are arranged above and along a distinct ridge, which runs parallel to the upper margin. When the 

 palpi are at rest, a row of these hairs disposed along the ridge, falls over the edge of the labrum. 



Mandible (PI. XVI, fig. 8). Distance between extremities of teeth 1 and 2 about 

 the same as that between 2 and 3. The latter teeth doublé. The 3 rd somewhat thicker, the 

 4 th small, 5 th and inferior «angle form together a blunt projection. The part of the mandible 

 behind the 3 rd tooth only slightly developed. 



55 



