354 T. H. Withers — The Cirripede Brachylepas cretacea. 



broken carinae and rostra, with several scuta and terga, obtained from 

 the Chalk of Eiigen by Mrs. Agnes Laur, and acquired by the British 

 Museum (Natural History). 



Examination of this material leaves little doubt that a single widely- 

 distributed but variable form is represented, and young valves 

 identical with the original of Emargimda (?) Naissanti can be seen 

 among the valves from Riigen. The Liineburg valves are on the 

 whole rather less strongly ornamented than those from other countries, 

 and this is possibly due to difference in habitat; but there is some 

 considerable variation in the sharpness of the longitudinal and trans- 

 verse ridges of the earinte and rostra from Riigen and England. 



Fig. 1. Pollicipes XMhjmerus, G. B. Sowerby. Living: Upper California, 

 Pacific, etc. (After Darwin.) Capitulum with two or more whorls of 

 valves under the rostrum ; latera gradually increasing in size towards the 

 capitulum ; peduncle generally two or three times as long as the capitulum. ' 

 ,, 2. P. mitclla, Linnaeus. Living: Philippines, China, etc. (After 

 Darwin.) Capitulum with one whorl of valves only under the rostrum ; 

 upper latera very narrow, three or four times as long as the lower latera, 

 which overlap each other laterally ; peduncle usually as long as the 

 capitulum, but in some cases considerably shorter. 



The carina and rostrum of Brachylepas Naissanti differ widely in, 

 shape from the same valves of Pollicipes fallax, now referred by 

 H. Woodward to the genus Brachylepas (1906), being much more 

 squat and semicircular, and their characteristic ornament readily 

 distinguishes even small fragments. The scuta, terga, and upper 

 latera of B. Naissanti, however, are very similar to the homologous 

 valves of P. fallax. The only difference as regards the terga and 

 upper latera, so far as one can judge from the tew valves of P. fallax 

 that have been examined, is that in B. Naissanti the transverse 

 ridges or zones of growth are not nearly so strongly marked, and 

 the basal portion of the terga is much more acute. The scuta of 



