EXPLORATION OF ALASKA. 195 
sperma in the cavity. The mucous gland large, 9.0 mm. long, by a 
height of 7.5 and a thickness of 4.0 mm.; whitish, yellowish chalk- 
white and yolk-yellow; the duct rather short, with the usual strong 
fold. The vestibulum with longitudinal folds. 
JORUNNA, Bergh. ' 
Jorunna, Bgh., Malacolog. Unters. (Semper, Philipp. I, ii) Heft x, 1876, 
p. 414, note. Gatt. nord. Doriden, Arch. fiir Naturges., xxxv, i, 1879, 
p- 346, . 
Corpus subdepressum ; dorsum minutissime granulatum, sub-asperum, 
branchia e foliis tripinnatis formata ; tentacula digitiformia; poda- 
rium sat latum, margine anteriore sulcatum, labio superiore latiore et 
medio fisso. 
Armatura labialis nulla. Radula rhachide nuda, pleuris multiden- 
tatis, dentibus hamatis. Penis stylo armatus; glandula et hasta 
amatoria. 
This genus was established by the author on the D. Johnstoni (1876) 
in reference to the results of the anatomical examination of Hancock 
and Embleton; he regarded it as nearly allied to the Kentrodorides, 
just founded by him.! After the present examination of the D. John- 
stont by the author he is not entirely certain of a generic difference 
between the Jorunne and the Kentrodorides. The latter have been 
examined only from rather insufficient material, and the hasta has not 
been seen in any of the species, only a papilla in connection with a 
peculiar gland; still the Kentrodorides are of a quite different habitus, 
very soft, and the upper lip of the anterior margin of the foot is more de- 
veloped, while the innermost plate of the tongue is somewhat different 
from the others. If not identical with the Kentrodorides, the Jorunne 
are certainly very nearly allied to them. ; 
The Jorunne are rather depressed; the back finely granulated, 
covered with equal minute papillule; the retractile gill formed of tri- 
pinnate leaves; the tentacles digitiform ; the foot rather broad, deeply 
grooved in the front margin, and the upper lip of this larger and cleft 
in the middle line. The lip-disk not armed, covered with a simple 
cuticula. The rhachis of the radula naked, the pleure with many 
hook-formed plates. In the vestibulum genitale are four apertures : 
' R. Bergh, Malacolog. Unters. (Semper, Philipp. II, ii) Heft x, 1876, 
p. 413-427, Tab. XLIX-LI. 
» Jorunna, Bjornis filia. Laxdila-Saga. Hafnize, 1826, p. 21. 
‘ 
