A REMARKABLE NEW CIRRIPEDE. 951 
undergone very little modification in structure from an ordinary 
pedunculate Cirripede. The fixed scutum and tergum have a 
greater transverse convexity than in an ordinary pedunculate 
Cirripede, but, unlike those of Verruca, they can be neealy 
identified. ame fact, they prove the correctness of Darwin’s inter- 
pretation of the valves in Verruca as deduced from a study of the 
valves of the young shell. As is shown by the right and left 
movable scuta and terga, it isa feature of both genera that either 
the right or left valves may be developed to torm the “ wall.” 
If we take such a pedunculate Cirripede as is included in the 
sub-genus Scillelepas of the genus Culantica, we see that the 
eapitulum is composed of two whorls of valves, the upper com- 
prising paired scuta and terga, anda carina, the lower whorl 
consisting of three pairs of latera, a rostrum, and a sub-carina. 
There is no upper lateral valve between the scutum and tergum, 
although the median lateral valve may be homologous with the 
valve that becomes an upper lateral valve in the more specialized 
forms of Scalpellum. Now if we imagine the almost equal 
development of the rostrum and carina, and the suppression on 
one side of the lateral valves, the scutum and tergum would be 
allowed to form that side of the wall, and the opposing scutum 
and tergum would have to lean over at a greater angle to meet 
them. We should then have only to suppress the sub-carina, 
the median latus, and the peduncle, to get a form such as 
Proverruca. This was evidently the history of the form, and 
although Scillelepas may not have been the actual ancestor, it 
must have been a form somewhat similar. Proverruca still 
retains the primitive structure of the valves, as is shown by the 
isolated examples, and the two lateral valves, regarded as homo- 
logous with the rostral- and the carinal-latus in the Pollicipedide, 
are two that remain of the three lateral valves. It is of much 
significance that of these two valves only the carinal-latus really 
for ms that part of the wall between the rostrum and carina. 
The rostral-latus overlaps for its whole length the lateral portion 
of the rostrum, and it certainly seems as though with the 
approaching attachment of the lateral portions of the rostrum 
and carina, the two lateral valves were on their way to sup- 
pression. We have only to imagine their absence, the meeting 
of the rostrum and carina, and the development of interlocking 
ribs to strengthen the attachment of the valves, te turn Proverruca 
into a typical Verruca (text-fig. 1, A, B.) 
We see that in the non-attachment of the rostrum and carina, 
the presence of two lateral valves, and in the structure of the fixed 
scutum and tergum, Proverruca is related to the Pollicipedide, 
but more particularly to the genus Calantica Gray. In the 
asymmetry of the shell owing to the unequal development of the 
valves on both sides, and in one of the scuta and terga forming 
the operculum, it is related to Verruca, and it is especially near to 
the recent deep-sea species with elevated shells. Proverruca un- 
doubtedly represents the ancestral type from which has arisen the 
