EEPOET ON THE NUDIBEANCHIATA. 
85 
consistency of the animal is not hard, the form is plump and slightly depressed ; the back 
more or less granular or tuberculate, the openings for the rhinophores simple; the 
tentacles short, thick folds at the sides of the small head, with an external furrow ; 
the retractile gill composed of a few tripinnate or quadripinnate leaves ; the foot 
broad, with a furrow on the anterior margin. The labial disk merely clothed by a 
simple, thick cuticle. The radula with naked rhackis ; the pleurae with numerous hook- 
shaped plates. The large ventricle free. Penis and vagina both unarmed. 
The Archidorides approach the Staurodorides in their general form and external 
features, but still more closely in their internal structure, though the latter are still distin- 
guished by their numerous and simply pinnate branchial leaves, and by the develop- 
ment of protecting tubercles on the margin of the rhinophore-holes and of the branchial 
cavity. 1 The Homoioclorides perhaps stand in still closer proximity to the Archidorides , 
though they differ specially from the latter in a peculiar armature of the vagina. 2 
Only a few species of the group are as yet known : — 
1. Archidoris tuberculata (Cuvier). 
North Atlantic, Mediterranean. 
2. Archidoris fiammea (Alder and Hancock). 
North Atlantic. 
3. Archidoris montereyensis (Cooper). 
North Pacific. 
4. Archidoris kerguelenensis, n. sp. 
North Pacific. 
5. Archidoris australis, n. sp. 
North Pacific. 
1. Archidoris kerguelenensis, n. sp. (PI. I. figs. 1-12). 
1 Doris tuberculata, Cuv. 1 Th. Studer, Die Fauna von Iverguelensland, Arcliiv f. Naturg., Jahrg. 
xlv.,Bd. i. p. 128, 1879. 
Habitat. — Kerguelen Islands, Pacific Ocean. 
The form mentioned by Studer is probably the same as that now described. There 
was only one individual of this species, taken January 17, 1874, off Royal Sound, 
Kerguelen, lat. 49° 40' S., long. 70° 20' E., depth 25 fathoms. 
1 Bergh, Malacolog. Untersuch., loc. cit., Heft xiv., 1878, p. 578 ; Supplementheft i., 1880, pp. 36-40. 
2 E. Bergh, Beitr. zur Kenntn. d. japan. Nudibr. IT., Verhandl. d. k. k. zool.-bot. Gesellscli. Wien, Bd. xxxi., 1881, 
pp. 222-227. 
