90 BULLETIN 60, UNITED STATES NATIONAL MUSEUM. 



The occludent margin of the scutum is convex; the strai^fht tero-al 

 marg-in is shorter than the carinal margin, which is straightened or a 

 little concave near the base, then strongly convex. The basal margin 

 is very short. An angle runs from the umbo to the apex, defining a 

 very narrow lanceolate ventral area. A curved ridge or angle runs to 

 the tergo-carinal angle. An oblique constriction or wide furrow defines 

 an obliquel}" sulcate basal area. Internally the scutum has a small 

 um1)onal tooth and a wide, low, and smooth basal callus. 



The tergum is rhombic, the occludent margin parallel with the 

 carinal, the latter more than half the length of the former. 



The carina (figs. 18, 19) is moderately curved, with convex roof. 

 The sides are narrow in the upper two-thirds, suddeid}' expanding in 

 the lower third, and marked with narrow oblique riblets. The umbo 

 is incurved and projects below the base of the scutum; the basal margin 

 is as long as that of the scutum and forms an obtuse angle with it. 

 Internallj^ the carina is concave throughout. The cavity of the base 

 is inclosed b}^ a concave plate with notched upper margin, the sides 

 being produced above in two short teeth. 



The peduncle is cylindric, oblique to the capitulum, blackish, trans- 

 versely wrinkled, and about one-fourth the length of the capitulum. 



Length 19, width 9, diameter 5.5 mm. Length of the carina, 13 mm. 



The teeth of the mandil)le are somewhat more slender and acute 

 than in P. lixmpfer!^ and the upper and lower margins are bearded 

 for a greater distance. The spines at the upper angle of the maxilla 

 are more slender than in P. ha&mjpferi. 



I have figured an intermediate segment from the sixth cirrus (Plate 

 V, fig. 11). There are four pairs of large and one pair of small spines 

 at intervals along the anterior side, and groups of 3 or 4 small spines 

 at each articulation on the posterior side. 



This species is related to P. carlnatum Hoek, but differs by the 

 strong concentric sculpture of the plates, the different form of the 

 carina, especially interiorly, and the diverse sculpture of the interior 

 of the scutum at its base. 



MEGALASMA RECTUM, new species. 

 Plate VII, figs. 10-H. 



7y/><^— Cat. No. 32895, U.S.N.M. 



Type-locality. — Alhatrosx Station 2042, east of New Jersey, near the 

 following Station, in 1,555 fathoms. 



Other localities.— '^o. 9016, U.S.N.M. Alhatross station 2041, north 

 latitude 39° 22' 50". west longitude 68° 25', in 1,608 fathoms, globi- 

 gerina ooze. 



The capitulum is twice as long as wide, rather plump in the lower 

 half, compressed above, the sides equally convex. The occludent 

 margin is nearlv straight, the carinal strongl}' convex. The valves 



