72 - FOSSIL CIRRIPEDIA. 
Valve much elongated, sub-rhomboidal ; whole surface rather plainly ribbed longitudinally. 
A larger rounded ridge, with the surface of the valve depressed on the carinal side of it, 
runs in a slightly curved line, at about one third of the entire width of the valve from the 
carinal margin, down to the sharp basal angle. Apex narrow, much produced: occludent 
margin about equal in length to the scutal margin: upper and lower carinal margins almost 
running into each other. Parallel to the occludent margin, the valve is depressed, with a 
raised plait in the middle of the depression. Except in the more elongated form, and in 
the character of the ridge running from the apex to the basal angle, this valve is barely 
distinguishable from the tergum of S. arcwatum (with its varieties) found in the Chalk 
Marl and Gault. 
Carina (fig. 4, a). In Mr. Tennant’s collection there is a carina from the Chalk of Kent, 
different from any other seen by me, and which, from being plainly ridged, or rather fur- 
rowed longitudinally, I provisionally describe here. Valve thin, triangular, moderately 
tapering; very slightly bowed inwards; transversely, very flatly arched; plainly sub- 
carinated ; lateral edges narrowly and much inflected ; basal margin rectangularly pointed. 
A very small portion of the valve projected freely. The internal concavity of the valve is 
angular, instead of, as usual, being rounded. ‘The whole exterior surface, except close on 
each side of the central ridge, is longitudinally furrowed. 
17, Potuicrpes seminatus. ‘Tab. IV, fig. 6. 
P. valvis longitudinaliter et transverse costatis: scutorum margine basali brevi, recto: 
cum margine occludente angulum rectum formante : costd, parictali,’ tenuissimd ab apice ad 
angulum prominentem basi-lateralem decurrente; hec valvam in duas partes inequales 
dividit, é quibus portio tergo-lateralis latior est. 
Valves longitudinally and transversely ridged: scuta with the basal margin short, 
straight, forming a rectangle with the occludent margin; a very narrow wall-sided ridge 
runs from the apex to the prominent baso-lateral angle, and divides the valve into two 
unequal portions, of which the tergo-lateral portion is the broadest. 
Chalk Detritus, Charing, Kent. Mus. Harris. 
General Remarks. 1 know this species only from one minute broken scutum (°15 of an 
inch in length), with its surface somewhat disintegrated; but it is certainly distinct from 
the other species hitherto described. The Chalk detritus at Charing is derived from the 
upper and lower Chalk and Chalk Marl. 
Scutum ; the surface is marked by narrow, square-edged, longitudinal ridges, placed 
rather distant from each other; each zone of growth appears (for the surface is much dis- 
integrated) to have had a prominent plait or ridge which, consequently, runs in lines 
transverse to the longitudinal ridges. The upper part of the valve is only moderately 
1 Parietali, i. e. lateribus utrinque perpendicularibus. 
