THE BARNACLES IN THE U. S. NATIONAL MUSEUM. 55 



The carinal latus is about twice as liigli as wide, with the umbo 

 slightly projecting- behind at the lower fifth of the carinal margin. 

 The carinal margin is slightly concave above the umbo, convex below 

 it. The lateral margin is nearl}^ parallel with the carinal. 



The very short peduncle is closely covered with rounded imbricat- 

 ing scales, in nine rows of about eight scales each. 



Length of the capitulum 10.5, width 5.3 mm. Length of the 

 peduncle 3.5 mm. Length of the carina 9, diameter at base 1.7 mm. 



This species, represented by an unique example, stands close to 

 S. novoselandlse Hoek, but differs by the shape of the scutum. In S. 

 minntnm and S. ahyasicola the carinal margin of the upper latus is 

 longer. It resembles S. idioplax in the shape of the scutum, but the 

 inframedian and upper latera differ. The American form of S. cari- 

 natuiii differs from 6', alhatrosuanuvi by having the urabones of the 

 carina and upper latus removed from the apices of these plates; and 

 the typical ,5'. carinatum further differs by the shape of the tergum. 

 In ventral view S. aJhatrossianurit resembles the Calif ornian S. per- 

 longuin Pilsbry. (Fig. 19.) 



GROUP OF SCALPELLUM AURIVILLII. 



Inframedian latus very narrow, widest at the base, tapering to the 

 acute apical umbo. 



SCALPELLUM PENTACRINARUM, new species. 



Type.— Ciii. No. 32870, U.S.N.M. 



Ty2)e locality. — Albatross Stations 2319-2350, off' Habana, Cuba, on 

 a pinnule of Pentacrimis. 



The capitulum is subtriangular, the slightly convex occludent mar- 

 gin about twice the length of either of the other sides of the triangle. 

 It is composed of thirteen plates, which are fully calcified, separated 

 by linear sutures, and without perceptible cuticle. The plates are 

 lilac tinted, nearly white near the occludent margin, marked with 

 fine lines of growth and the scutum, tergum, and upper latus have 

 also fine, low radial striae. 



The scutum is long and narrow, widest at the base, which occupies 

 full}' three-fourths the width of the capitulum at that place. The 

 occludent margin is straight except near the summit, where it curves 

 slightly inward. The long, straight lateral margin converges slightly 

 upward tow-ard the occludent, so that the plate is narrower at the 

 tergo-lateral angle than at the base. The straight basal margin makes 

 a right angle w ith the occludent margin. The acute apex is at the 

 occludent margin. A low, narrow liblet runs from the apex to the 

 baso-lateral angle. 



The tergum is a little longer and wider than the scutum, triangular, 

 with erect apex. The oc(!ludent margin is slightly convex. The 



