60 FOSSIL CIRRIPEUIA. 



[^.] Scuta, costd, nonnumquam subobsoletd, ah apice ad centrum marginis hasilis 

 decur rente} 



' 10. POLLICIPES CARINATUS. Tab. Ill, fig. 9. 



PoLLiciPEs CARINATUS. PliUlippi. EnuiTi. Mollusc. Siciliac, 1836, Tab. xii, figs. 26, 28. 



P. scutis crassiuscnlis ad formam trianguH cequianguU accedentihus ; margine occludente externe costd 

 humuli Jirmato ; costd Jirmii ab apice ad centrum marginis hasulis decurrente ; mnrgine basali recto; angulo 

 baso-laterali truncato, brevi ; segmentum tergo-IateruJe ex lineis incrementi rejlexis formatum, deest. Carind 

 externe valde carinatd cum suico laterali ad utrumque latus. 



Scuta moderately thick, in shape nearly an equilateral triangle ; occludent margin exteriorly strengthened 

 by a slight ridge ; a strong ridge runs from the apex to the middle of the basal margin ; basal margin 

 straight ; baso-lateral angle truncated, short : the tergo-lateral portion, formed by upturned lines of growth, 

 is absent. Carina, exteriorly, strongly cariuated, with a lateral furrow on each side. 



Tertiary ; Messina, Sicily. 



I owe to the great kindness of Dr. Phillippi an examination of an authentic series of specimens. Valves 

 rather thick, with the lines of growth plain, and with a few fine striae radiating from their apices : these 

 striae are sometimes so conspicuous, that I have doubted whether the species ought not to have been 

 placed in the next section. 



Scuta (fig. 9, d, e) ; triangular, with the apex slightly bowed over towards the terga ; moderately convex ; 

 occludent margin slightly arched, about equal in length to the slightly hoUowed-out tergo-lateral margin ; 

 basal margin nearly straight, though formed by two lines meeting each other, sometimes with the 

 rostral half not descending so low as the other half; this margin forms equal angles with the other two 

 margins. The baso-lateral angle is obliquely truncated : there is no tergo-lateral slip formed by upturned 

 zones of growth. The occludent margin is exteriorly strengthened in a manner only just perceptible 

 by a flattened rim. A strong, conspicuous, and prominent ridge runs, in a slightly curved course, from 

 the apex to a point in the basal margin, rather nearer to the rostral than to the baso-lateral angle ; 

 this point just perceptibly projects beyond the rest of the basal margin : the ridge is either moderately 

 sharp, or broad and flat-topped ; it marks the line of chief curvature of the valve. Internally (e), the pit for 

 the adductor muscle is not very strongly developed, and to a different degree in difierent specimens : the 

 internal surface of the centre of the apex is prominent ; on its tergal side there is no furrow, but a rect- 

 angular indentation formed by a remarkably wide, flat, smooth ledge, which runs down, narrowing, to the 

 baso-lateral angle ; hence the scuta along the whole of this side, especially in the upper part, must have widely 

 overlapped the terga, in a manner and to a degree I have not seen equalled in any other Pollicipes ; but the 

 two valves cannot be said to have been articulated together. The internal occludent edge widens a little in 

 the upper part, and is here divided by an oblique line, with the lines of growth apparently discontinuous on 

 opposite sides of it, into two portions, of which the inner portion is slightly more prominent than the outer, 

 I have already alluded to the fact, that in some specimens the scuta are strongly ribbed longitudinally, 

 in some very faintly striated, and in others smooth. 



Terga (fig. 9, a, h) ; sub-rhomboidal, elongated, exteriorly convex, internally very slightly concave : upper 

 part very thick and solid, with a considerable portion freely projecting, and internally marked by lines of 

 growth : along the middle of the portion thus marked, there is a slight longitudinal depression, which is worth 

 remarking, inasmuch as (judging from a conspicuous and analogous character in certain recent species of 

 Lithotrya) it was probably caused by the internal central crest of the upper part of the carina. Occludent 

 margin slightly convex, very little shorter than the scutal margin ; upper and lower carinal margins nearly 

 equal in length ; they meet each other at a very open angle : upper carinal and occludent margins meet each 

 other at an angle of only a little above 50°. A prominent, strongly marked ridge, (with both sides of the 



