CLASS GASTROPODA 
23 
at the extremity, furnished with two long, cylindrical, tentacular, retractile, 
appendages. Suckers in two small, compact bunches, like bunches of 
grapes. These parts whitish. Pedal disk cordiform, purple with a black 
spot. Foot long, slender, linguliform. Branchiae short, inconspicuous. 
Length, 1.0; diameter of body, .3; spread of pinnae, 1.15 in. (Dali.) 
Type in United States National Museum, No. 301. Type locality, 
North Pacific Ocean, lat. 37° 8' N., long. 136° 10' W. 
Range. Northeast Pacific off the California coast in lat. 37° N. and 
northward to lat. 45° N. 
Family DESMOPTERIDAE 
Desmopterus pacificus Essenberg, 1919 
University of California, Zoological Publications , 19, No. 2:85; figs. 1, 2. 
The body is somewhat barrel-shaped. The anterior or head end is 
bent ventral. The shell is absent, but the body is covered completely by a 
transparent integument. The strongly developed wings, the epipodea, are 
attached to the antero-ventral portion of the body and are fused in the 
middle. Their posterior margin extends beyond the posterior extremity 
of the body. It is deeply indented, the entire margin being divided into 
five distinct lobes, one median and two lateral on each side. The anterior 
margin of each wing is only slightly curved and is without indentations or 
lobes. Between the two lobes of the posterior margin of each wing are 
inserted the epipodial tentacles. These are short, their length being only 
one and one-half times their width. Each tentacle is supported with a 
strong nerve and is covered with cilia. Judging by each nerve supply 
these tentacles are sensory, probably tractile organs. The wings are 
supplied with well-developed nerves. One strong nerve is sent to each 
lobe, subdividing and spreading there into several smaller branches, and 
one large nerve goes to each epipodial tentacle. Long., 1-2 mm., width, 
4-5 mm., measured from tip to tip of the spread wings. (Christine Essen¬ 
berg.) 
Type in University of California Collection. Type locality, off San 
Diego, 32° 53' N. latitude. 
Range. Off Southern California. 
Family ACTEONIDAE 
Genus ACTEON Montfort, 1810 
Shell solid, ovate, with a conical, many-whorled spire, spirally grooved 
or punctate-striate; aperture long, narrow, rounded in front; outer lip 
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