18 
THE VOYAGE OE H.M.S. CHALLENGER. 
This specimen, like almost all the other specimens of Glaucus atlanticus dis- 
sected by me, was infested by Distoma glauci, 1 a form closely allied to Distoma 
appendiculatum of G-. Wagner. 2 The animal (PL X. figs. 5-1 7) varies in length from - 41 mm. 
to T27 mm. The suckers are very large, the posterior nearly double the size of the 
anterior, measuring in large individuals T6 mm. by ‘2 mm. The tail was nearly always 
more or less retracted, sometimes entirely concealed (fig. 5). In several individuals 
(perhaps of a different species I) there was no tail, and the hinder part of the body was 
filled with yellowish egg-like bodies (fig. 10). 
Glaucus longicirrus, Reinhclt., Bergh. ? 
(?) Glaucus pacificus, Eschsch., Zool. Atl., Hft. 4, p. 16, pi. xix. fig. 4. 
„ ,, Lesson, Voyage de la Coquille, Zool., t. ii. p. 288. 3 
Glaucus longicirrus , Bergh, loc. cit., pp. 291-295, Taf. viii. B. 
A specimen of Glaucus captured in the Pacific at the surface, July 1875, perhaps 
belongs to this species. 
The specimen was preserved on a slide in glycerine, and measured 12 mm. in length. 
The number of papillae on the first arm was fifteen or sixteen, on the second eight or 
nine; in the third series there were from five to six, and there seemed to be a fourth 
group with one or two papillae. The longest papilla measured 7 mm. 
Glaucilla brictreus (Reinhdt.). 
(?) Glaucus draco, Eschsch., Zool. Atl., Heft 4, p. 16, Taf. xix. fig. 5. 
,, „ E., Lesson, Voy. de. la Coquille, t. ii. p. 288. 
(?) Glaucus distichoichus, d’Orb., Voy. dans lAm6r. merid., 1844, p. 196, pi. xiv. figs. 1-3. 
Glaucilla briareus, Bergh, loc, cit., pp. 300-302, Taf. ix. b. 
Three small specimens captured in March 1875, in the West Pacific, belong possibly 
to this species, but having been, like the last species, very badly preserved, it is impossible 
to speak with certainty. 
The length of the body was from P5 to 3 mm. The number of papillae appeared to 
be smaller than in the original specimens examined by me. 
Janolus, n. gen. 
Forma corporis cum crista interrhinophoriali et ano postico-mediano sicut in Janis, 
limbus podarii latus. 
Mandibulae colossese, margine masticatorio non denticulate. Dentes mediani linguae 
hamo rudimentario ; laterales numerosi, angusti, hamo breviori curvato. 
1 Bergh, loc. cit., pp. 282-283. 
2 G. Wagner, Archivf. Naturgesch., Jahrg. xxvi. Bd. i., 1860, pp. 165-194, Taf. viii., ix. 
3 Reinhardt regarded the last two forms as specifically distinct, merely on account of a difference in colour. 
