538 Dr. H. Woodioard — On Fossil Shells from Sumatra. 



tuclinally. The apex in PL cataphracta, and less markedly so in 

 the recent PL concinna, exhibits the same embryonal character. 



Dimensions of fossil: — Length of smaller shell 18 mm.; of larger 

 specimen (anterior canal partly broken off) estimated at 21 mm. ; 

 breadth smaller shell 1\ mm. ; larger specimen 8^ mm. 



Formation : — In bluish-grey Tertiary Marl-clay. 



Locality : — Government of the West Coast of Sumatra. 



53. Phos Borneensis, Sowerby, 1866. PL XIV. Fig. 4a, b. 

 Shell subfusiform, turrited, encircled with distant spiral lira? and 



prominent nodular rounded ribs, finely striated between the ribs ; 

 costae narrow, somewhat distant (the regularity of the ornamenta- 

 tion is occasionally broken by a few discontinuous varices, more 

 prominent than the equidistant costee) ; thickened on the varix 

 behind the aperture ; aperture narrow below ; canal subrostrate ; lip 

 corrugated within; whorls 7-8 in number. 



Dimensions : — Height of shell 21 mm. ; breadth of shell 10 mm. 



This shell appears not to be separable specifically from the living 

 Bornean form. The whorls are perhaps a trifle less shouldered at 

 the upper part, the spiral lira? are more numerous, and the minute 

 or subordinate sculpture is also of a finer character. 



The thread-like lirations within the aperture are more numerous, 

 and the oblique simple keel which winds round the extremity of the 

 body- whorl is more distinct. These are but trifling differences, and 

 hardly sufficient to entitle the Sumatran fossil to separate specific 

 rank. The general facies of this fossil and normal examples of the 

 living shell is remarkably similar, the proportion of the whorls being 

 identical. 



Formation : — In bluish-grey Tertiary Marl-clay. 



Locality : — Government of the West Coast of Sumatra. 



54. Phos subplicatus, H. Woodw. (not figured). 



Shell solid, turrited, lira? scabrose, costse nodular, spirally cinctured ; 

 spire short, 5-6 whorls, whorls somewhat rounded; costse rounded, 

 tolerably close, more numerous near the aperture. 



Dimensions : — Height of shell 12 mm.; greatest breadth 7 mm. 



The shell of this species is much shorter in the spire, and 

 increases in size more rapidly than that of the preceding one. It 

 closely resembles the Phos plicatus, A. Adams (Proc. Zool. Soc. 1859). 



It differs from the recent Phos plicatus in the less angularity of 

 the whorls and the more rounded character of the ribs ; they are 

 also less close-set than in the recent form. 



We have ventured to consider this as distinct. 



Formation and Locality : — Found with the preceding species. 



55. Turbinella subcostata, H. Woodw. PL XIV. Fig. 5, a, b. 



Shell fusiform, subturrited, thick ; spire with the sutures some- 

 what squamose, whorls about 7 in number, with prominent rounded 

 costa? transversely plicated ; plica? about three in number (more 

 numerous upon the body-whorl) ; plications acute ; aperture small, 

 ovate, and canaliculate, posteriorly notched, sulcated within; columella 

 thickened and subtransversely triplicated ; canal moderately long. 



