56 
THE VOYAGE OF H.M.S. CHALLENGER. 
Euplocamus, Philippi. 
Euplocamus, Philippi, Enum. Mollusc. Sicilian, i, 1836, p. 103. 
„ Alder, Note on Euplocamus, Triopa, and Idalia, Ann. and Mag. Nat. Hist., ser. 
vol. xv., 1845, p. 262. 
„ Gray, Guide, Dist. Moll. Brit. Mus., part i., 1857, p. 215. 
„ Alder and Hancock, Monogr. Brit. Nudibr. Moll, pt. vii., 1855, p. xix. 
„ R. Bergh, Beitr. zu einer Monogr. d. Polyceraden. I., Verhandl. d. k. k. zool.-bot. 
Gesellsch. Wien, Bd. xxix., 1880, pp. 6 2 3-6 3 9. 1 
Corpus vix depressum. Tentacula plicseformia, apice auriculatim soluta ; rhinophoria 
retractilia, clavo perfoliato. Branchia 3 (5) foliata. Margo frontalis sicut margo dorsalis 
appendicibus arborescentibus ornati. 
Orificium oris utrinque lamella triangulari, e baculis minutis dense confertis com- 
posita armatum. Lingua rhachide nuda, pleuris dentibus lateralibus majoribus 2-3 et 
serie dentium externorum breviori (5-6) vel longiori (18-35) armatis. 
Prostata magna spermatothecam et spermatocystam amplectens. 
The genus Euplocamus was established by Philippi 2 in 1836, but in 1844 the name 
was withdrawn by him, under the erroneous impression that it was synonymous with 
Idalia, . & genus founded by Leuckart in 1828. Although Alder, in 1845, showed that 
Euplocamus was really distinct from Idalia, 3 the mistake of Philippi was repeated in the 
handbooks of Philippi, Woodward, and others, as well as throughout the compilatory works 
of Gray , 4 Hermannsen/ and others, and in the memoir of Loven . 6 The differences 
between Euplocamus and Idalia were clearly formulated by Alder and Hancock in 
1855, and by. Gray in 1857, but nevertheless they have subsequently been frequently 
confounded , 7 or Euplocamus has been united with Triopa . 8 This controversy was finally 
settled by a memoir written by myself in 1880, in which the external characters of 
Euplocamus, as well as its anatomy, are treated of. 
Euplocamus has the frontal margin only slightly prominent but strong, somewhat 
branched frontal appendages, of the same nature as the lateral appendages of the back. 
The tentacles are mere folds of the skin, free at one edge like the tip of an ear ; the retrac- 
tile rhinophoria have the club perfoliated. The branchia has from three to five tripinnate 
1 This generic name has already been applied to a Lepidopteron by Latreille (1809), and later to a bird by 
Temminck (1838). If it is therefore to be changed, I would suggest Kaloplocamus. 
2 Philippi, Enum. Mollusc. Sicilige, ii., 1844, p. 76. 
3 Alder, Note on Euplocamus, Triopa, and Idalia, Ann. and Mag. Nat. Hist., ser. vol. xv., 1845, p. 262. 
4 Gray, List, etc., Proc. Zool. Soc., 1847, p. 165. — Gray, Figures of Mollusc. Anirn., vol. iv., 1850, p. 105. 
5 Hermannsen, Index gen. Malacozoor. prim., i., 1846, p. 435. 
6 Loven, Index Moll., 1846, p. 5. 
7 Chenu, Man. de Malacol., t. i, 1859, p. 406. — Verany, Catal. des Moll, de, &c., Nice. Journ. de Concliyl., t. iv., 1853, 
p. 386. 
8 Abraham, Revision of Anthobranchiate Nudibranchiate Mollusca, Proc. Zool. Soc., 1877, p. 230. Hancock, 
however, had long ago pointed out the great differences between Euplocamus and Triopa (Alder and Hancock, Monogr. 
Brit. Nudibr. Moll., pi. vi., 1854, Gen. Triopa, Note). 
