182 BULLETIN OF THE BUREAU OF FISHERIES. 



Terga large and rhombic, with erect apices. Tli :cludent margin is straight, the carinal margin 



straight above but convex where in contact with the carina. The scutal margin is nearly straight. The 

 carina is extremely broad basally, the roof convex, the lateral angles prominent. It is curved through- 

 out, but the upper half more so; apex terminal. 



The upper lateral plate is triangular, with apical nucleus. Its scutal margin is longer than either of 

 the other two, which aresubequal. The rostrum is an excessively small, very narrow plate, visible below 

 tlie apices of the rostral hit era. The rostral lateral plates are low, obliquely triangular, with the apices 

 contiguous at the median ventral line. The lateral edge is covered by the imbricating rostral margin 

 of the inframedian lateral plate. The inframodian lateral plates are triangular, nearly equilateral, with 

 apical umbo. The carinal lateral plates are subtriangular, embracing the lateral angles of the carina; 

 their apices are recurved and project slightly. The peduncle is covered with horizontal, somewhat 

 imbricating, smooth scabs, which are rather sparsely tomentose, the hairs very delicate and rather long. 

 Its total length is unknown, as the individual has been removed from its support by cutting the peduncle. 



Length of capitulum 25, greatest breadth 16 mm.; greatest thickness, across the carino-lateral plates, 

 12 mm. Length of carina 21.5, diameter at base 9.5 mm. 



Type, no. 32410 U. S. National Museum, from Albatross station 4181, near Kauai, in 811 fathoms, 

 bottom manganese sand and globigerina ooze. 



Scalpellum rubrum Hoek, from near Luzon, agrees with 5. havaiense in the proportions of the valves, 

 but it differs strikingly in color and surface sculpture. &. hirsutum is also related, though obviously 

 different. 



Scalpellum pacificum, n. sp. 



[PI. iv. tig. 3, 4.] 



A form closely related to Scalpellum australicum Hoek. 



The capitulum is acutely ovate, compressed, composed of 14 valves closely juxtaposed; these are 

 covered with a very thin brownish film, which near the occludent margin bears a few scattered long 

 hairs. The valves are sculptured with numerous, but not crowded, radiating threads, and on each of 

 the side valves there is one more prominent ridge or angle extending from the umbo to the opposite 

 margin, dividing the valve into two areas. 



The scutum is convex, divided into two nearly equal areas by a slightly curved diagonal rib; the 

 occludent and opposite lateral margins are slightly arcuate, the tergal and basal margins straight, the 

 latter at an angle of 90 or a trifle less with the occludent border. 



The tergum is larger than any other plate, triangular, with a distinct diagonal rib parting the narrow 

 carinal from the large and triangular anterior area. The occludent margin is convex, the carinal a little 

 undulating and the tergal or basal margin straight. The apex stands erect. 



The carina is simply arched, with the flat roof bordered by distinct ridges; sides at about right 

 angles with the roof, and broader near the upper extremity of the valve. 



The upper lateral plate is trapeziform with the apex superior, the scutal margin concave, the basal 

 and tergal margins equal, straight, and the very short carinal margin also straight. 



The rostral lateral plate is subquadrate, short and broad, the length being about half the width. 

 The curved beaks are connate on the occludent border above the rostrum, and do not project percep- 

 tibly. The upper and lower borders of the plate are subparallel and straight; the rostral border is 

 concave. From the umbo a curved rib runs to the posterior basal angle. The rostrum is rudimentary, 

 merely a linear trace. 



The inframedian lateral plate is extremely narrow, linear, wedge-shaped, the narrow apex above. 

 There is a low cord along each edge, anil the apex is curved rostrad. 



The carinal lateral plate is irregularly trapezoidal, with the umbo projecting a little beyond the 

 carina. The carinal margin is straight; upper margin very oblique, straight; lateral margin short. 

 straight. In carinal aspect, the two carinal lat era appear as contiguous tricostate brackets under the 

 two lateral ribs of the carina. The peduncle is short, wider above, covered with wide low scales, about 

 seven scales in any longitudinal row. 



Length of capitulum of type, from station 3907, 10.5 mm., greatest breadth S.5 mm., diameter 3.8 

 mm.; length of peduncle 3.5 mm. 



