44 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



internally, except near the occludent end, where the tergum has a 

 small projection. 



The apices of the fixed scutum and tergum are shortly prolonged 

 and curve toward one another. The paries of the fixed scutum is 

 ridged parallel to lines of growth. The tergal area or radius is very 

 narrow, the rostral area larger than the paries. The interior is 

 smooth, without pit or myophore. 



The fixed tergum is the highest plate. It has a very narrow, raised 

 paries, and rather large, subequal scutal and carinal radiiform 

 triangles. 



The carina and rostrum are transversely ridged at the ends, but 

 in front interlock by about four subequal teeth in each, these termi- 

 nating as many strong, imbricate-sculptured radial ribs. 



Length between apices of rostrum and carina 9 mm.; height of 

 fixed tergum 8.3 mm. 



Cirrus i has subequal rami of about 10 and 11 segments (pi. 8, fig. 

 3a). Cirrus ii has the anterior ramus three-fourths the length of the 

 posterior, blunt at the distal end; segments 7 and 13 (pi. 8, fig. 3). 

 The rami of other cirri are subequal, and bear throe pairs of spines 

 on the segments (pi. 8, fig. 36, cirrus vi). Terminal appendage of 10 

 segments, 2.6 mm. long, being a trifle longer than the protopod of 

 cirrus vi, which is 2.4 mm. long (pi. 9, fig. 1). 



This fine Verruca is known by a single individual, which grew 

 upon a small irregular object, not preserved. This doubtless affected 

 the shape of the walls, which enlarge upward, more I think, than 

 they would on a supporting object of more ample dimensions. 



The species is related to V. ratlibuniana (p. 41), which came from 

 a neighboring station, but its chief affinity is with F. gibbosa Hoek, 

 from the Challenger station 317, northeast of the Falkland Islands, 

 in 1,035 fathoms, bottom temperature 1.7 C. I note the following 

 differences between the two forms: (1) In V. bicornuta the rostrum 

 and carina interlock by at least four subequal teeth in each plate, 

 terminating as many ribs and fitting into the ends of as many fur- 

 rows, while in V. gibbosa "both valves are furnished with one very 

 distinct and two rather shallow furrows," one upper tooth in each 

 plate therefore predominating conspicuously over the others. The 

 articular rib, next to the lower one, of the movable scutum is better 

 developed in V. bicornuta, and separated from the lower rib by a 

 narrow, rather deep and smooth furrow. The movable tergum is a 

 little wider in V. bicornuta. V. mitra Hoek, from about 70 south 

 latitude, is very closely related to F. gibbosa, and differs from F. 

 bicornuta in much the same features. 



Another somewhat related but antipodal species is F. sulcata Hoek 

 from near the Kermadec Islands. 



