REPORT ON THE CIRRIPEDIA. 100 



Observations. — This species seems to be rather common at very great dipt lis in 

 the Atlantic Ocean. As far as known at present, these are the deepest places inhabited 

 by Cirripedia. As well by the structure of the female (and hermaphrodite?) as by 

 that of the male specimen, the species closely resembles other species living at a considerable 

 depth, and also some from much lesser depths. The deep-sea species, as a true typical 

 specimen of which the present form must be regarded, have no distinct character of 

 their own. The very rudimentary condition of their complemcntal males is observed in 

 some of the shallow-water species also. 



Scalpellum regium, var. ovale (PI. V. figs. 5, 6). 



Together with six specimens of Scalpellum regium, a specimen was dredged, which 

 in most respects resembles the typical species, but which differs from it in general shape 

 and in the length of the peduncle. Its capitulum is not quadrangular but long-oval, 

 and this is caused by the greater length of the carina, the apex of which is situated at 

 a small distance from the apex of the tergum. The tergum itself is a great deal smaller, 

 and has about the same area as the scutum. The carina has the sides almost 

 undeveloped. Of the valves of the lower whorl, the rostrum is small and very narrow ; 

 the rostral latus and the infra-median latus much resemble those of Scalpellum regium. 

 The carinal latus, however, is a great deal larger; higher in the first place. Moreover, the 

 ridges which divide the same valve in Scalpellum regium into distinct triangles are by no 

 means so distinct in the variety. At the carinal side the two valves are separated by a 

 membranous part, which probably represents the sub-carina. 



The length of the capitulum in the only specimen is 31 mm., whereas the peduncle 

 measures 22 mm. The capitulum is covered by membrane, but even when studied with 

 a lens this membrane appears smooth, that is, not hairy as in the typical specimens. The 

 peduncle has an irregular cylindrical shape ; the scales are distinct in the inferior part of 

 the peduncle, but totally covered by membrane near the capitulum. There are about 

 eleven longitudinal rows, some of which number on less than twenty scales. 



This variety was furnished with a complemental male, which was still in the pupa- 

 stage. This, however, is no reason, I think, why we should consider the specimen as a 

 young specimen of Scalpellum regium; for, in the first place, I often observed males 

 in that condition attached to the same female together with well-developed males, 

 and in the second place, because one of the specimens of Scalpellum regium, the capitulum 

 of which measured only 2.3"5 mm., was furnished with as many as four well-developed 

 males. 



The animal was taken at Station 61, June 17, 1873 ; Lit. 34° 54' X., long. 5G° 38' 

 W. ; depth, 2850 fathoms; bottom temperature, 1°'5 C. ; bottom, grey ooze. 



