730 MR. E. A. SMITH ON NEW SHELLS FROM [June 18, 



apex, olive-brown, more or less coated with a black earthy deposit. 

 Whorls probably about 9 in number, the remaining four or five 

 slightly convex, spirally sulcate, and longitudinally sculptured with 

 coarsish flexuous lines of growth; ridges between the sulci about 10 

 in the penultimate whorl and 18 in the last, those near the base 

 separated by wider sulci than above. Aperture oval, acuminate 

 superiorly and very slightly effuse at the base, occupying about $ of 

 the supposed entire length of the shell, sordid bluish within ; lip 

 very thin, broadly sinuated above and somewhat prominent below 

 the middle. Columella whitish, moderately arcuate. 



Supposed total length 23 millim. ; actual length of five remaining 

 whorls 19, diameter 7^; aperture 7\ long, 4^ wide. 



Hab. Formosa (Dickson). 



This species resembles M. dolorosa, Gould, to some extent ; how- 

 ever, it i; distinguishable on account of more elongated whorls and 

 coarser spiral sulci. Some of the lines of growth here and there are 

 well marked, and give the whorls a subplicated appearance. 



Bullia persica. (Plate XL VI. fig. 11.) 



Shell ovate-acuminate superiorly, greyish or lavender-colour, 

 whitish at the upper part of the whorls, with the callous band at their 

 base white, bordered below by a brown line at the suture ; and the 

 base or cauda of the last whorl is also white. Whorls 6, the first 

 two smooth, convex, the rest spirally sulcated, the ridges between 

 the sulci 8 in number in the upper whorls and about 16 in the last, 

 whereof 12 are above and 4 below the acute ridge or keel, which 

 winds round the lower portion of the whorl. Of these ridges the 

 four immediately below the suture are more or less white, granulous 

 through being crossed by oblique sulci, which only extend from the 

 suture a short distance. Aperture deep brown within, with a paler 

 or white border at the outer lip and over the basal sinus, and a little 

 longer than the spire. Columella moderately arched, and coated 

 with a thinnish white enamel. Basal sinus rather broad and deep. 



Length 24 millim., diameter 10; aperture 12 long, 7 broad. 



Hab. Bushire, Persian Gulf. 



Two specimens of this very interesting species have recently been 

 presented to the Museum by Mr. A. S. Betts. The peculiar form 

 and colouring, the granular ridges at the upper part of the whorl, 

 and the brown aperture with the white margin to the labrum and 

 basal sinus are the most obvious distinguishing characters of the 

 species. 



Ostrea, sp., adhering to Trochus (Polydonta) maculatus, Linn. 

 (Plate XL VI. fig. 12.) 



This is a remarkable instance in which a shell has assumed, to a 

 certain extent, the sculpture of another to which it has adhered. 

 This assumption or mimicry of the surface of other shells and foreign 

 substances has already been noticed in other species of Ostrea and 

 other genera, and is common to most forms of the genus Myochama. 

 The same process which effects so remarkable a change in the normal 



