324 T. H. WitJiers — Tlie Cirripede BracJiylepas cretacea. 



to save fcome of the lower latera which were still held together by the 

 matrix eveu after soaking. These valves imdoubtedh' represent 

 a colony of individuals the remains of which were embedded together, 

 and proof of this is afforded by the fact that the carinse, rostra, scuta, 

 terga, and upper latera include quite young valves measuring about 

 2 mm. in size, the others ranging up to as much as 125 mm. 

 Moreover, not a single valve of any other species of Cirripede was 

 found with them. 



Of the English representatives of Brachjlepas Naissanti, the carina, 

 rostrum, and lower latera only have been described, these valves being 

 represented in position in the remarkable specimen in the collection of 

 Dr. A. W. Ptowe from the B. muct-onata-zo-no of Norwich. As already 

 stated in the History (see p. 322), Zittel (1885) figured detached 

 examples of all the valves of this form from the Chalk of Liineburg, 

 with the exception of the upper latera, under the name Pollicipes 

 l(Bvissimus, Quenstedt. Unfortunately he gave no descri2)tion of them, 

 neither does he say whether they were found separately or associated. 

 In these circumstances, and since these newly found valves complete 

 our knowledge of the cajiitulum of Brachylepas Naismnti, it is here 

 proposed to give descriptions of the several valves, and to discuss what 

 further light they thrown on this interesting form. 



Carina (Fig. 1) semi-conical, inner margin straight or bowed outwards ; ^ apex 

 acute ; basal margin semicircular, somewhat concave. Inner surface thickened 

 near the lateral margins, this portion being marked with fine growth-Hnes, 

 which are continued under the apex to about one-sixth the extent of the valve ; 

 these growth-hnes indicate the extent to which the valve projected freely. 

 External surface marked with several feebly marked ridges radiating from the 

 apex ; these are more pronounced near the apex and die out towards the basal 

 margin. These ridges are crossed by feebly swollen bands, parallel to the basal 

 margin, giving a cancellated appearance to the valve, especially near the apex 

 where the ridges are much sharper. The ends of the transverse ridges give 

 a serrated appearance to the lateral margins. 



Eostrum (Fig. 2) semiconical, smaller and proportionally broader than the 

 carina, inner margin straight or bowed outwards. Inner surface thickened near 

 the lateral margins, and marked by growth-lines, which are continued under 

 the apex to about half the length of the valve ; the free projection of this valve 

 therefore was proportionally much greater than that of the carina. Outer 

 surface ornamented as in the carina, but more pronounced ; and the ridges 

 radiating from the apex, especially in young specimens, give the basal margin 

 _a toothed appearance. 



Scutum (Fig. 3) almost triangular ; occludent margin convex and in its upper 

 part bowed towards the terga ; basal margin slightly concave ; tergal margin in 

 its upper part slightly concave, and its lower part slightly convex ; apex and 

 basi-lateral angle acute. Ad-oceludent portion moderately convex transversely, 

 and on reaching a line from the apex to the basi-lateral angle, rising up to form 

 a fold or ridge which on the tergal side is sharply folded downwards and 

 inwards, from which the tergal jjortion is abruptly deflected. Parallel with the 

 occludent margin, a narrow slip of the valve is bent downwards and forms an 

 indistinct ridge on the upper surface, on which the growth-lines are directed 

 upwards towards the apex. Inner occludent edge thickened, flat, narrow, and 

 marked by lines of growth ; a slight ridge runs obhquely from the tergal margin 



' The carina and rostrum of this Cirripede are either straight or outwardly 

 bowed, a feature that I have observed in certain fossil and recent species of 

 Pollicipes. It does not appear to be of specific importance. A rostrum of this 

 species from the Chalk of Norwich in the British Museum (Natural History), 

 registered I. 14028, is considerably bowed outwards. 



