DALL: MOLLUSCA AND BRACHIOPODA. 433 
of the rostrum corresponding to the dorsal area smooth. Lon. of shell, 27; of 
posterior end, 16; alt. 17; diam. 15 mm. 
U.S. S. “Albatross,” station 3392, in the Gulf of Panama, in 1270 fathoms, 
hard bottom, temperature 36°.4 F. 
It is possible that more material may show that this is merely a variety of 
C. planetica, but for the present it seems safer to keep them separate. As in all 
these species, the basal margins are somewhat flexuous. Measurements have 
been made for the length of the shell parallel to the hinge line, and the height of 
the shell is taken at right angles to this length. 
Cuspidaria (Cardiomya) planetica Da tt, n. sp. 
This species has a generally similar aspect to the C. pseustes above described 
and differs in the following particulars: the rostrum is less constricted at the 
proximal end, so that the whole shell is more attenuated backward; there is not 
so much distinction between the disk and the rostrum; the impressed area, along 
the dorsal margin, is smaller and is not amphidetic, but ceases to be defined in 
front of the beaks; the radial major threads appear stronger and less numerous ; 
the chondrophore or fossette is much less conspicuous and is formed by a small 
pit in the cavity under and almost behind the hinge margin, while in pseustes it 
is a comparatively large vertically projecting spoon-shaped process; the general 
form of C. planetica is more elongate and the anterior patulous extension is directed 
forward rather than obliquely downward; lastly C. planetica is uniformly smaller. 
Length of shell, 24; of posterior part behind the beaks, 13; alt. 14; diam. 
11 mm. 
U.S. S. “ Albatross,” station 2925, off San Diego, California, in 339 fathoms, 
mud, bottom temperature 42°.9 F. Types U. S. N. Mus. 110,720. Also at 
station 3400, east of the Galapagos Islands, in 1322 fathoms, ooze, temperature 
36°; station 3059, off Siletz Bay, Oregon, in 77 fathoms, mud, temperature’45°.1 ; 
and station 3609, in Bering Sea, southeast of the Pribiloff Islands, in 74 fathoms, 
mud and sand, bottom temperature 38° F. It has also been collected from deep 
water, 85 fathoms, in Captain’s Harbor, Unalashka, Aleutian Islands. The ex- 
treme stations are about 3500 miles apart. 
A few specimen stations have been selected to show the immense range of this 
widely distributed species. It will be noted that it descends from about 80 
fathoms in the north to over 1300 fathoms in the tropics, following the sea 
isotherms, and this I may add without altering its appearance in the least, 
notwithstanding the immense difference in pressure. Living in these depths 
near the Galapagos Islands, it would be no surprise to find it anywhere still 
farther south. 
Cuspidaria (Luzonia) chilensis Dar. 
Cuspidaria (Luzonia) chilensis Dall, Proc. U. S. Nat. Mus., 1889, 12, p. 282, pl. 13, 
fig. 13. 
VOL. XLIII. — NO. 6 28 
