the Cirripede Subgenus Scillelepas. 263 
trustworthy evidence, then the species, P. ooliticus and 
P. aalensis*, P. quenstedti,and P. (?) lotharingicus +, Méchin, 
all of which have valves similar to S. gavey?, are probably 
nearly related, and belong to Sezllelepas. 
Against this view is the fact that Darwin has described 
and figured in his Monograph (p. 52, pl. ili. fig. 2 5) a com- 
paratively large rostrum of P, ooliticus, similar to but rather 
wider than the carina. I am not at all sure, however, that 
in this particular Darwin has allowed sufficiently for varia- 
tion, and that the valve really is a rather wide carina; a view 
of the inner surface of the valve would have decided the 
matter. 
Zittel has referred the species P. quenstedti to his genus 
Archeolepas, but the valves appear to differ in structure from 
the valves in Archwolepas, and this view is strengthened by 
the fact that there is among the valves of P. quenstedti 
figured by Max Schlosser (1881) $ a rostrum which agrees 
much more with the rostrum of Scillelepas, being decidedly 
different in shape from the rostrum in undoubted species of 
Archeolepas. 
Altogether the evidence, while not conclusive, is in favour 
of referring S. gaveyi to Scillelepas, and it is clear that there 
is no indication of its affinity with Pollicipes. I am inclined 
to think that further material will show this species, together 
with Pollicipes ooliticus, P. aalensis, P. quenstedti, P, (?) 
lotharingicus, and probably one or two other Jurassic species, 
to belong to Scillelepas, or, at least, to a genus nearly related 
thereto. 
Comparison with other Species.—Pollicipes (?) lotharingicus, 
Méchin, from the spinatus-zone of Agincourt (Meurthe-et- 
Moselle), France, is the only other species known from the 
Pliensbachian, although it occurs at a somewhat higher 
horizon than S. gavey?. Only a single carina and tergum 
are known ; the carina appears to be much more attenuated 
and tapering than S. gavey?; the tergum differs in its pro- 
portions, having a shorter occludent margin, which makes a 
larger angle with the carinal margin, and the scutal margin 
is proportionally much longer, and the angles formed by thie 
zones of growth appear to have their apices much nearer to 
the carinal margin. Moreover, the valves do not appear to 
be marked with longitudinal lines, since no mention is made 
of them in the description, and nothing is said of the fine 
* Richardson, L., 1908, Geol. Mag. dec. v. vol. v. p. 352, text-fig. ; 
Withers, T. H., 1911, Proc. Cotteswold Nat. F. C. vol. xvii. pt. ii. p. 275. 
+ Méchin, A., 1901, Buil. Soc. Sci. Nancy, ser. 3, vol. ii. fase. i. p. 16, pl. 
t Schlosser, Max, 1881, ‘ Paleontographica,’ Bd. xxviii. p. 60, pl. viii. 
2. 8. 
Lo} 
