340 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
less promoted; between the major radii in the wide interspaces there are in each 
case a pair of minor radii without whorls of hairs; these radii do not appear to 
cover any shelly ridges or ribs, the surface under them is not, in the specimens 
examined, perceptibly raised; the interior is porcellanous white, with a broad, 
strong muscular impression having a wide anterior hiatus ; when the apex is not 
central it is more or less anterior to the centre. Diameter of average specimen, 
5.0; height, 2.5 mm. 
U.S. S. “Albatross,” station 4656, off Sechura Bay, Peru, in S. Lat. 6° 55’ 
and W. Lon. 83° 34’, in 2222 fathoms, green mud, bottom temperature 35°.2 F. 
U.S. N. Mus. 110,570. Seated on cuttle beak, with Cocculina. 
Another Cephalopod beak bearing similar excavations but no specimens was 
dredged off Aguja Point, Peru, at station 4654, in 1036 fathoms, mud, tempera- 
ture 37°.3 F. 
Cocculinidae. 
COCCULINA Dat. 
Cocculina Datu, Proc. U. S. N. Mus., 1881, p. 402; Bull. Mus. Comp. Zool., 1889, 
18, p. 845; type, C. rathbuni Dall, 1881. 
This genus is represented in nearly all parts of the deep sea which have been 
explored. 
Cocculina agassizii Datt, n. sp. 
Shell small, white, covered with a strong light, olive-colored periostracum, be- 
neath which it is chalky, ovate-quadrate, high, with the apex about the posterior 
third, and the anterior longer slope roundly arcuate ; the periostracum is finely, 
closely, radially threaded, the threads seem to bear very short projecting hairs, 
but neither the threads nor the hairs appear to correspond to any sculpture of the 
shell; on drying, the periostracum immediately detached itself from the upper 
part of the shell, showing beneath it only very fine, irregularly concentric lines ; 
toward the margin it seemed to be more closely attached to the shell and, by its 
contraction in drying, began at once to split the shell, obliging me to return it at 
once to the liquid from which it had been taken, or it would have gone to pieces 
entirely ; interior of the shell smooth, white, with a broad, short, horseshoe shaped 
muscular impression with a wide anterior hiatus at about the anterior third of the 
length; nucleus small, bulbous, produced, hardly spiral, but decurved; the shell 
enlarges suddenly on entering the nepionic stage; animal as usual, with a single 
posterior epipodial filament on each side. Alt., 2.0; length, 3.5; width, 2.5 mm. 
U.S. 8. “ Albatross,” station 4630, Gulf of Panama, in 556 fathoms, sand, 
temperature 40°.5 F., on a fragment of wood. U.S. N. Mus. 110,660. 
