110 BULLETIN 60;, UNITED STATES NATIONAL MUSEUM. 



an individual only 3 mm. long, but it differs by the better developed 

 articular ridges of the movable scutum, which in K radiata occupy a 

 comparatively much narrower portion of the surface; by the less 

 curved ridges of the movable tergum, the weak radial grooves of the 

 fixed scutum, etc. F. en(jhjpta of tlie same size as the type of iV. 

 radiata would evidently be quite unlike that species. 



The rostrum, carina, fixed scutvim, and fixed tergum, when the plates 

 are detached, are seen to be conspicuouslj" vaulted or decked over near 

 the beaks. No such structure is seen in V. calotheca^ in which the 

 plates are simple inside. 



VERRUCA CALOTHECA, new species. 

 Plate XI, figs. 1, 2, 3. 



Type.—Q'd.t. No. 32907, U.S.N.M. 



Type-locality. — Albatross Station 2415, north latitude 30° 44', west 

 longitude 79° 26', 440 fathoms, on Scalpel lum superhuin. 



The shell is white, depressed, with subcircular base, slightly wider 

 than long; end walls vertical; carino-rostral wall sloping outward, the 

 opposite (scuto-tergal) wall overhanging. The movable scutum and 

 tergum lie nearly parallel to the plane of the base. 



The movable scutum is subtriangular, its surface divided into two 

 areas of nearly equal size. The outer area is sculptured with wide 

 transverse ribs parted by much narrower interstices. The tergal area 

 has four arcuate articular ridges, the middle two deeply cut into trans- 

 verse tubercles; fourth rib narrower and less deeply sculptured; first 

 rib delicately striate transversely. 



The tergum is quadrangular, the upper margin shorter than the basal, 

 the carinal margin arcuate. The surface is divided into two subequal 

 areas, the carinal area transversely ribbed. Scutal area sculptured 

 with four articular ribs, the first finely sculptured with thin arcuate 

 transverse lamella?, the other ribs transversely cut into tubercles, which 

 have the imbricating appearance of roof tiles. The second rib is the 

 smallest, and hardly reaches to the apex, which is somewhat recurved. 

 The furrow between the first and second ribs is wider than the others. 



The fixed scutum is quadrangular, with parallel u])per and basal 

 margins. The apex is somewhat recurved and produced. A diagonal 

 rib from the apex divides the surface into equal triangles. The upper 

 or occludent triangular area is sculptured with irregular, rather wideh" 

 spaced, vertical grooves and two shallow radial furrows. The lower 

 area has a rather rude, irregular, and weak sculpture of grooves par- 

 allel to the base. The tergal margin is straight and vertical. 



The fixed tergum is very irregular in shape. The surface is radially 

 divided into three areas, the middle one triangular and raised, without 

 distinct sculpture. The scutal area is sunken, rather narrow, and 

 very obliquely, finely costulate. The carinal area is wide, obliquely 



