DALL!: MOLLUSCA AND BRACHIOPODA. 353 
Puncturella (Cranopsis) expansa Datu.» 
Plate 4, figures 5, 10, 11. 
Rimula? expansa Dall, Proc. U.S. Nat. Mus., 1896, 18, p. 10. 
Shell low, rounded, expanded; apex small, prominent, subcentral, recurved to 
the right; foramen like an exclamation point without the dot (!), the small end 
anterior, the suture in front of the foramen inconspicuous, marked by a narrow 
raised line on the interior of the shell; anterior slope convex, gently rounded ; 
posterior a little excavated; sculpture of evenly spaced, similar, close, fine, 
rounded threads overrunning radiating, rounded, little elevated threads of three 
sizes, the larger starting at the apex, the others intercalary toward the periphery 
as the interspaces widen; margin of the shell slightly crenulated by the sculp- 
ture; interior smooth, yellowish white, the septum convexly arched without but- 
tresses. Height, 10; length, 32; width, 26 mm. 
U.S. S. “ Albatross,” station 3358, Gulf of Panama, in 555 fathoms, sand, bot- 
tom temperature 40°.2 F.; and station 3407, off the Galapagos Islands, in 835 
fathoms, ooze, bottom temperature 37°.2 F. U.S.N. Mus. 122,966 and 122,967, 
the latter being the figured type. 
This species recalls P. asturiana Fischer, but is larger, lower, and more ex- 
panded, a thinner shell, and with more delicate sculpture. 
This appears to be the largest species of the genus yet described. A verge is 
present at the seat of the right tentacle in male specimens. 
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POLYPLACOPHORA. 
Eochitonia Dati, 1889. 
Lepidopleuridae. 
LEPIDOPLEURUS Risso. 
Lepidopleurus (Risso) Hist. Nat. Eur. Mérid., 1826, 4, p. 267; not of Carpenter, 
1863. 
Leptochiton, Gray, P. Z. S. Lond., 1847, p. 127; Carpenter (Ms.) Dall, Proc. U. S. 
Nat. Mus., 1878, 1, p. 314. 
Lepidopleurus Sars, Moll. Reg. Arct. Norv., 1878, p. 110; Pilsbry, Mon. Polypla- 
cophora, 1892, p. 2. 
The chitons of the deep sea and archibenthal regions almost exclusively be- 
long to the present genus, and present an extremely uniform appearance. 
VOL. XLIII. — NO. 6 23 
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