44 
THE YOYAGE OF H.M.S. CHALLENGER. 
as it does in Scyllcea, and there is no trace of the peculiar relations between the liver 
and the branchial organs which are seen in the kladohepatic Nudibranchiata. There is 
no trace of the sanguineous gland, which is characteristic of the holohepatic Nudi- 
branchiata. The hermaphrodite gland, as in the last-mentioned group, surrounds the 
liver, and is not separate from it as in Scyllcea. The spermatlieca is large, but there is 
no spermatocyst present. The penis is unarmed. 
The Family of the Tritoniadse as now known 1 includes two (or three) generic groups. 
Firstly, Tritonia, which may again be divided into (l) Tritonia, characterised by the 
great development of papillae upon the frontal margin and by the radula possessing a 
great number of lateral teeth ; and (2) Candiellct, characterised by the development of 
finger-shaped processes upon the frontal margin, and by the smaller number of lateral teeth 
on the radula. Secondly Marionia, and the somewhat doubtful genus HancocJda of 
Gosse, 2 which perhaps belongs to this family also. 
The Tritoniadae are carnivorous animals, feeding chiefly on Alcyonarians and allied 
forms. The spaivn of some species of Tritonia from the North Atlantic has been 
described. Nothing is known about their development ; Gosse simply mentions the 
Nautiloid shell in HancocJcia. 
I. Tritonia, Cuvier. 
Limbus frontalis papilligerus vel digitatus. Yentriculus non armatus. 
The Tritoniae proper differ from the Marioniae by the simple papillae of the frontal veil, 
and by the stomach being unarmed. The genus may be divided into two subgenera. 3 
Sub-genus 1 . Tritonia. 
Margo veli frontalis papilliger. Radula dentibus lateralibus numerosis. 
The genus contains the following species : — 
1. Tritonia hombergi, Cuvier. 
Atlantic Ocean, Mediterranean. 
2. Tritonia rubra, Leuckart. 
Red Sea. 
3. Tritonia tetraquetra (Pallas). 
Pacific Ocean, neighbourhood of Aleutian Islands. 
1 Of. My monograph of the Tritoniadse, which will shortly be published, and which will form Heft xv. of my 
Malacologische Untersuchungen (in Semper, Reisen im Archip. d. Philipp. Th. II. Bd. ii.). 
2 P. H. Gosse, On Hancockia eudactylota, Ann. and Mag. Nat. Hist., ser. 4, vol. xx., 1877, pp. 316-319, 
pi. xi. 
3 Cf. My monograph on Tritoniadee, loc. cit. 
