64 BULLETIN ()(), UNITED STATES NATIONAL MUSEUM. 



slightly toward the rostral })order. The umbo is probably apic-al, but 

 it is not readily visible. 



The carinal latiis is irregular! }■ trapezoidal, perhaps a little g-reater 

 in area than the upper latus. The basal and lateral margins are about 

 equal, the oblique upper margin a little longer. The obtuse umbo is 

 at about the lower third of the carinal margin. It does not project 

 beyond the carina. The plate is sculptured with strong radial riblets. 

 In dorsal view the carinal latera are seen to be strongly tricostate, 

 and meet in an irregular suture. 



The peduncle is very short, closely covered with large, projecting, 

 transversely lengthened scales, in about eight rows of eight scales 

 each. 



Length of the capitulum, 16; breadth, 7.7 nun. Length of the 

 peduncle, 3 mm. Length of the carina, 12.5; diameter at base, 2.5 mm. 



The linear inf ramedian latus and the strong radial sculpture of the 

 carinal latus are the more striking characters of this species. It is 

 most nearly related to S. auriviUu., but differs in numerous particu- 

 lars, as set forth in the key to species. (Pig. 25.) 



SCALPELLUM AURIVILLII, new species. 



%>f.— Cat. No. 82805 U.S.N.M. 



Type-locality. — Alhatross Station 2731, oti' Cape Hatteras, north 

 latitude 36° 45', west longitude 74° 28', in 781 fathoms, growing on 

 Sea Ipellum velutin um . 



Other localities.— ]^o. 12286, Albatross Station 2728, north latitude 

 36° 30', west longitude 74° 33' in 850 fathoms. No. 11757, Alhatross 

 Station 2710, north latitude 40° 06', west longitude m° 01' 30", in 984 

 fathoms. No. 9026, Fish Commission Station 1123, off Marthfls Vine- 

 yard, 787 fathoms, bottom temperature 39"^ F., on Acanella. No. 

 10779, Alhatross Station 2529, north latitude 41° 03' 30", west longi- 

 tude 'o'o'^ 14', in 662 fathoms, gray mud, bottom temperature 38.7° F. 



The capitulum is rhombic-oblong, twice as long as wide, the ventral 

 margin slightly convex; composed of 13 fully calcified plates. Cuticle 

 very thin and smooth. Sutures linear. The plates are marked with 

 fine, irregular lines of growth, and minute, inconspicuous radial stride. 



The length of the scutum is somewhat more then twice its greatest 

 width. The occludent margin is straight except near the apex, where 

 it bends l)ack. The lateral margin is concave below the tergo-internal 

 angle, becoming convex in the middle. The basal margin is nearly 

 straight, and forms an angle slightly less than a right angle with the 

 occludent margin. The plate is widest in the middle. The acute apex 

 is recurved within the- ventral border. 



The tergum is nuich longer and wider than the scutum, triangular. 

 The occludent margin is convex, nearly three-fourths as long as the 



