46 PROCEEDINGS OF THE ACADEMY OF [1880. 



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. II, ii) Heft x, 1876, 

 p. 414, note. Gatt. nord. Doriden, Arch, fiir Naturges., xxxv, i, 1879, 

 p. 34«. 



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- 

 stoni by the author he is not entirely certain of a generic difference 

 between the Jorunnce^ 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 Jorunnce 

 are certainly very nearly allied to them. 



The Jorunnce are rather depressed ; the back finely granulated, 

 covered with equal minute papillulog ; the retractile gill formed of tri- 

 pinnate leaves ; the tentacles digitifoi-m ; 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 pleurae 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. Laxdiila-Saga. Hafniae, 1826, p. 21. 



