THE BARNACLES IN THE V. B. NATIONAL MUSEUM. 



48 



The rostral latera are small, wedge-shaped, their acute apices 

 meeting' on the ventral line. 



The inframedian latus is of very irregular shape, narrowly oblong, 

 with one upper angle produced toward the carina. The umbo is at 

 the upper third of the plate on the rostral side, the wedge-shaped 

 surface ))elow it being raised above the rest of the plate. 



The carinal latus is imperfectly triangular, with a convex margin 

 projecting below the carina, the um})o being a little recurved, situated 

 at the bases of the ribs of the carina and at about a third the height of 

 the plate. The basal margin is about equal to the lateral margin. 

 The latter is sinuous, concave in 

 the middle, for the reception of the 

 upper lobe of the inframedian plate. 



The peduncle is shorter than the 

 capitulum, closely covered with 

 imbricating scales about 1 mm. 

 wide. 



Length of the capitulum 17, 

 breadth 8.7 mm. Length of the 

 peduncle 9 mm. Length of the 

 carina 16, diameter at base 3.3 mm. 



This species closeh' resembles S. 

 rathbima^^ from which it differs 

 chiefly by the absence of radial 

 riblets on the scuta and upper 

 latera, the wider roof of the carina, 

 its bordering ribs not sulcate, and 

 by the very much larger scales of 

 the peduncle. 

 Tathhun» in the very peculiar shape of the inframedian latera. (Fig. 12.) 



. Fig. 12. — ScALPELLUMSOROR. a, LATERAL view; 6, 



O. ^OVOV IS like h. CARINAL VIEW; C, ROSTRAL VIEW, X 2. 



GROUP OF SCALPELLI^M ARIETINUM. 



The carinal latera project far downward and flare outward below 

 the carina, with the umbones at their free ends. This modification is 

 unlike any other hitherto known species. 



SCALPELLUM ARIETINUM, new species. 



Type.—Q^t. No. 9792, U.S.N.M. 



Type-locality. — Albatross Station 240."), Gulf of Mexico, nortii lati- 

 tude 28° 45', west longitude 85° 02', in 30 fathoms. 



Othrr loealitws.— Cat. No. 10055. Alhatross Station 2315, Straits 

 of Florida, north latitude 24° 26', west longitude 81° 48' 15" in 37 

 fathoms, on spines of Oidaris tribuloides. 



The capitulum is subtrapezoidal, the occlndent border straight; of 

 a crimson color (or more or less tinted with crimson on a yellowish 



