8 
THE VOYAGE OF H.M.S. CHALLENGER. 
The bulbus pharyngeus and the mandibles resemble those of Phylliroe. I examined 
the radula in two individuals, and found it to consist of fifteen to sixteen series of 
teeth. Further back there were only five fully-developed series, but two other imper- 
fectly developed series were present. The total number of series thus amounted to 
twenty-two and twenty-three in the two specimens. The number of teeth in the series 
was 6-1-6 ; their form has been already described by me. 
The salivary glands, with the rest of the digestive tract and its hepatic sacs, were quite 
as in Phylliroe. The renal chamber (fig. 4, e.e) long and somewhat irregularly con- 
tracted ; the renal syrinx (fig. 4, d) resembles that of Phylliroe, and is about 0‘2 mm. in 
length; the ureter (fig. 4 ,f) as in Phylliroe. Two hermaphrodite glands are present, 
and closely resemble in form and colour those of Phylliroe atlantica, as does also the 
penis. There is no spermatheca. 
2. Acura lanceolata, Bergh. 
Phylliroe lanceolata, Bergh, Malacolog. Untersuch., loc. cit., p. 241, Taf. xxxi. fig. 5. 
To this species is probably to be referred an Acura captured in the West Pacific, on 
the surface, March 27, 1875. The specimen was preserved on a slide. It measured 
nearly 13 mm. in length, and 3 mm. in height. The form of the body agrees closely 
with the figure given by Semper. As far as could be made out, a renal sac was present, 
and there appeared to be two hermaphrodite glands, as also mentioned by Semper ; the 
hepatic caeca were quite as in the former species. 1 
Family jFolidiad^e. 
Of this large Family only a few forms were captured during the expedition. 
Fiona, Alder and Hancock. 
Fiona, Alder and Hancock, — Forbes and Hanley, British Mollusca, vol. iii., 1853, p. x. 
,, Alder and Hancock, Monog. Brit. Nudibr. Moll., part 7, 1855, p. 52, pi. xxxviii. a. 
,, Bergh, Beitr. zur Kenntn. d. iEolidiaden I., Verhandl. d. k. k. zool.-bot. Gesellsek. 
Wien, xxiii., 1873, pp. 605-610; — V., loc. cit., xxvii., 1877, pp. 823, 824. 
,, Bergh, On the Nudibr. Gastr. Moll, of the North Pacific Ocean (in Hall, Scientific 
Results of the Exploration of Alaska, vol. i., art. v.) part 1, 1879, pp. 85 (141)— 88 (144). 
Hymenceolis, A. Costa, Annuario del MuseozooLdi Napoli, III., 1866, pp. 64-80, — IV., 1867, p. 28. 
Corpus elongatum, gracile ; rhinophoria et tentacula subsimilia, simplicia. Papillae 
(dorsal es) cuti firmius afiixse, elongatae, ob membranam branchial em quasi alatae ; bursa 
cnidophora nulla. Anus dorsalis dextrorsum situs ; aperturae genitales discretae, geminae. 
1 Semper only found three caeca — the antero-inferior being absent. This must be merely an individual abnormality. 
In a specimen of Phylliroe atlantica which I examined, the antero-superior caecum was reduced to a mere rudiment 
(Bergh, loc. cit., Taf. xxix. fig. If.). 
