THE BARNACLES IN THE U. S. NATIONAL MUSEUM. 31 



Attached to one of the specimens 1 found the single example of S. 

 auriinllil mcertum. The occurrence in a Pacific station of two forms 

 so closely related to Atlantic species as these ma}' g-ive rise to serious 

 doubts as to the proper labeling of the material; yet 1 have been 

 unable to obtain any information indicating that the barnacles were 

 obtained elsewhere than at the station given. 



SCALPELLUM REGINA, new species. 

 Plate II, tigs. 4, 5, (5. 



Type.— C?ii. No. 9647, U.S.N.M. 



Type-locality. — Alhatross Station 2oTG, Gulf of Mexico, north lati- 

 tude 29° 03', west longitude 88° 16', in 324 fathoms; gray mud. 



Capitulum of 14 plates, in general shape like 8. regium ; moder- 

 ately compressed; covered with a densely and shortly pilose cuticle. 

 In adult capitula the plates are separated by rather wide chitinous 

 sutures, but in 3^oung ones the}" are in contact. The plates are weakly 

 sculptured with widely spaced low wrinkles along- the lines of growth, 

 as in S. glganteum. 



The scutum is large, twice as long as wide. The occludent margin 

 is arcuate above, the acuminate apex being somewhat recurved. Basal 

 and lateral margins straight, tergal margin a little concave. 



The tergum is about equal to the scutum in area and decidedly 

 longer. Occludent margin straight, the carinal and scutal margins 

 about equally arcuate. It is divided into two areas by a straight apico- 

 basal ridge, the carinal area being about half as wide as the scutal. 

 The greatest width of the tergum is less than half its length. 



The carina is separated from the scuta and latera by a rather wide 

 chitinous space. It is regularly arcuate or more curved above. 

 Umbo terminal at the apex, which is pushed slightly between the 

 scuta. The roof is slightly convex, bounded by angles but not ridges 

 (Plate II, fig. 4, carina in transverse section). The sides are narrow 

 throughout, and the base projects in a triangle between the carinal 

 latera. The lines of growth on the roof are V-shaped. 



The upper latus has the tergal and scutal margins straight, a little 

 concave near the acuminate apex, the carinal and basal margins 

 rounded. Umbo at the apex. It is sculptured with growth lines 

 only. 



The rostrum is very small, triangular, and separates the rostral latera 

 slightly. 



The rostral latus is low, with the upper and lower margins parallel. 



The inframedian latus is small, triangular, with the basal margin 

 longest, the umbo apical. 



The carinal latus is of very irregular shape. The convex posterior 

 margins project beyond the carina, and the two latera meet below it. 



