60 
THE VOYAGE OF H.M.S. CHALLENGER. 
portion, and contrasting with the straight anterior region. This curvature is dorsal over 
the greater portion of its length, but is slightly ventral towards the apex. The 
embryonic portion is not separated by a projecting ring from the rest of the shell. The 
length is also considerable, 20 mm. 
Habitat. — South Atlantic Ocean, 33° 30' S., 1° O' W. 
# 8. Clio polita (Craven, MS.) (PI. II. figs. 4-6). 
1880. Clcodora falcata, Pfeifer, Die Pteropoden des Hamburger Museums, Abhandl. Naturwiss. 
Ver. Hamburg, P>d. vii. p. 96, pi. vii. fig. 19 (not Gould, 1852). 
Balantium politum, Craven, MS. (British Museum). 
Characters and Description. — Shell, slender, narrow posteriorly, smooth over its 
entire surface, more bulging ventrally than dorsally, exhibiting on the former surface 
four slight longitudinal grooves, but none on the latter. The lateral keels are well- 
marked, sharp, projecting, parallel to the axis of the shell, more delicate than those of 
Clio balantium, and not hollow-edged. The dorsal curvature is uniform and continuous. 
Pfeffer has indeed figured two specimens of this species, one of which exhibits a regular 
curvature (fig. 196), while the other is much recurved posteriorly (fig. 19a), and has 
based his description on the latter. But all the specimens which I have seen from the 
collections of the “Valorous” and the Challenger also resemble fig. 196, which I am 
therefore warranted in regarding as the normal type. The middle of the lips does not 
project anteriorly. The embryonic shell has a bulging oval form, rounded on its posterior 
portion, and separated from the rest of the shell by a well-marked constriction, limited 
by a small projecting ring. 
The animal I have not observed. The soft parts are “ dunkel-schwarz-violett ” 
according to Pfeffer. 
Dimensions, 10 to 11 mm. 
Habitat. — North Atlantic Ocean, Davis Strait (“Valorous” Expedition), 44° N., 31° 
W. (Hamburg Museum). 
Challenger Specimens. — Deposit shells. 
Station 78, July 10, 1873 ; off the Azores; lat. 37° 26' N., long. 25° 13' W.; depth, 
1000 fathoms ; bottom, volcanic mud. 
Station 85, July 19, 1873 ; off Palma Island (Canaries) ; lat. 28° 42' N., long. 18° 6' W.; 
depth, 1125 fathoms; bottom, volcanic mud. 
Station 120, September 9, 1873 ; off the coast of South America, between Pernambuco 
and Bahia; lat. 8° 37' S., long. 34° 28' W.; depth, 675 fathoms; bottom, red mud. 
