CLASS GASTROPODA 
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quem in Ph. finmarchica appresso. Superficie lineis spiralibus tenuissimus, 
duplicatis, catenulato inflexis obducta. Radulae formula: I.O.I.2. uncinis 
lamellas laterales edentulae longitudine aequantibus. Long., 3; lat., 2.5-2 
mm. (Aurivillius.) 
Shell very thin, fragile, pellucid, oblong-ovate; whorls 3-4. Aperture 
ample, expanded at base, contracted above, the outer lip more appressed 
than in P. finmarchica. Surface covered with spiral, very delicate pairs 
of lines, scalloped chain-wise. (Tryon and Pilsbry, Manual of Conchology.) 
Type locality, 73° 5' N., 144° 20' E., and 70° 28' N., 164° 10' E. in 
8-9 fathoms. 
Range. Arctic Sea to Nanaimo, Vancouver Island, British Columbia. 
Philine bakeri Dali, 1919 
Proceedings of the Uftited States National Museum, 56:300. 
Shell minute, translucent, of two or more whorls, enfolded, except the 
subglobular nucleus by the last whorl; apex blunt; last whorl narrow, 
obliquely expanded in front; sculpture of numerous, fine, incised, punc¬ 
tate, spiral lines with wider interspaces; axis gyrate, pervious; aperture as 
long as the shell, narrow behind with a very slight sulcus, but widely 
expanded in front; outer lip thin, sharp, straight, inner lip hardly glazed. 
Height, 2; diameter, 1.25 mm. (Dali.) 
Type in United States National Museum, No. 225194. Type locality, 
off South Coronado Island. 
Range. Known only from type locality. 
Family GASTROPTERIDAE 
Genus GASTROPTERON Kosse, 1813 
Shell wholly covered, consisting of a minute nautiloid, calcareous spire 
and a large open last whorl of very delicate membrane or cuticle. 
Gastropteron swims rapidly by means of its large parapodial lobes, which 
are used as wings. (Tryon and Pilsbry, Manual of Conchology .) 
Type. Gastropteron rubrmn Rafinesque. 
Distribution. Mediterranean, Unalaska. 
Gastropteron pacificum Bergh, 1893 
Zoologische Jahrbuch, 7:303; PI. 16, fig. 28. 
The shell is as in rubrum, the calcified portion measuring .6 to .66 mm., 
chalk-white, radially striate, and very fragile, the large cutkular last 
whorl as in G. rubrum. (Tryon and Pilsbry, Manual of Conchology.) 
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