100 PROCEEDINGS OF THE ACADEMY OP [1879. 



lip-plates of rather different kind and nature. With the Doriop- 

 sidee (Porostomata) the Dorididse agree in the presence of two 

 spermatothecse, and of a vascular gland connected with the cen- 

 tral nervous system. 



There have been detected but a small number of the generic 

 forms and species belonging to this large family during Dall's 

 expeditions. 



ARCHIDORIS, Bergh. 

 Doris anct. 



Archidoris, Bergh, Malac. Unters. (Semper, Pbilipp. ii. Heft xiv. p. 616, 

 1878). 



Corpus sat molle subdepression. Tentacula hum ilia, plicse-for- 

 mia intus altiora. Dorsum tuberculosum et granulosum. Bran- 

 chia (retractilis) e foliis tripinnatis formata. Podarium sat latum, 

 margine anteriore superficialiter sulcatum. 



Armatura labialis nulla. Radula rhachide nuda, pleuris multi- 

 dentates ; dentes hamati. Ventriculus liber. Penis biennis. 



When Linne, in the tenth edition of his Systema Naturae 

 (1758), founded the genus Doris, he referred but one species to it 

 (cf. my Mai. Unters. [in Semper, Reise Philipp. II. ii.], Heft x. 

 1876, p. 388), his D. verrucosa. This, which was founded only on 

 the figures of Seba and Rumphius, is probably indeterminable, 

 and the Doris of the tenth edition of the Syst. Nat. should, there- 

 fore, not have been retained. 



In the twelfth edition (1767) the genus embraces, beside D. ver- 

 rucosa, which still figures as first species, three other forms, the 

 D. bilamellata, D. Isevis, and D. argo. 



One of these should become the type of the restricted genus 

 Doris, but which ? It would be much better to quite do away 

 with the name Doris as a generic designation (especially as it was 

 also used in auother sense by Linne, for the animal of various 

 shell-bearing mollusks), and under this view the genus Archidoris 

 has been formed. 



This generic group, which is congeneric with the first of the sec- 

 tions established by Alder and Hancock (Monogr. part vii. 1855, 

 p. xvi.) in their systematic prospectus, is rather distinctly marked. 

 The animals are of a rather hard consistency, of a robust, and 

 not much depressed form. The tentacles are formed in folds 

 higher inwards. The openings of the rhinoj)horia are simple. The 

 back more or less granulous and tuberculous. The (retractile) 



