372 Mr. T. H. Withers on the 
three pair of lower latera, making sixteen valves: I believe 
there must have existed some other latera, but probably 
only a few more; for these valves, especially the carinal 
pair, are much larger, in proportion to the scuta and terga, 
than in any recent Pollicipes. Probably the lower latera, 
together with the sub-rostrum, and perhaps a sub-carina, 
formed only a single lower whorl.” 
For some years now I have not been altogether satisfied 
in my own mind with Darwin’s interpretation of these 
remains, and more especially’their reference to the genus 
Pollicipes, but,in view of Darwin’s opinion as to the number 
of valves forming the capitulum, it was necessary to get 
proof before raising any discussion, and by the preparation 
of a number of specimens this has now been obtained. 
In 1910 (p. 499, text-fig. 4) I figured a small incomplete 
eapitulum of P. unguis showing the right side, and this 
consisted of the carina, scutum, tergum, upper latus, and 
carinal latus. That specimen not only showed the scutum, 
unknown to Darwin, but the valves were preserved in their 
natural position, aud it proved the position of the carinal 
latus. Darwin certainly did recognise this latter valve of 
P. unguis as a carinal latus, but, curiously enough, the 
homologous valve in the closely-related species P. glaber 
(1851, pl. ii. fig. 107) was regarded by him as a “ Latus 
(probably from near the rostrum).” 
Two specimens carry the evidence a stage further. One 
(Pl. V. fig. 1) in the Geological Department of the British 
Museum, registered 59802, exhibited the inner surface of 
the valves of the right side of an incomplete capitulum, and, 
when these were filled with plaster and the matrix taken 
away from their upper surface, the valves were seen to be 
almost in their natural position and to consist of the carina, 
tergum, carinal latus, avd inframedian latus. The second 
specimen (Pl. V. fig. 2) is in the Sedgwick Museum, 
Cambridge (Wiltshire collection), and exhibits the carina, 
and on each side the carinal latus, followed by the left and 
right inframedian latus. 
Turning now to other specimens in the Geological Depart- 
ment of the British Museum, one, registered 44300, shows 
remains of more than one capitulum. From this specimen 
were obtained five peduncular plates, of which two are 
figured (Pl. V. figs. 9, 10). There is on the matrix, in 
addition to a carina, paired terga, and upper latus, a left 
carinal latus and two other lateral valves attached together 
(Pl. V. fig. 3). Now one of these last two valves is the 
opposing valve of that which we know from specimen 59802 
