542 PROF. C. H. o'dONOGHUE : REPORT ON 
whetlier the liver remains in one compact mass or is split up and branclied. 
The two groups defined in this way, however, are separated by other 
associated anatomical differences, that indicate clearly a wider gap between 
them than is perhaps suggested by the mere condition of the liver. 
Tribe A. Holohepatica. 
Nudibranchs in which the liver forms a compact mass, neither branched 
nor divided, and usually accompanied by the following characters. There is 
complete external symmetry ; the vent usually lies in the mid-dorsal line and 
is surrounded by a circle of branchial plumes ; the radula is of moderate or 
considerable width, save in the family Dendrodoridae (Doriopsidaj) ; mandibles 
are rare ; the hermaphrodite gland is usually spread over the liver as a layer, 
but sometimes forms a discrete mass ; as a rule, the genital ducts are 
triaulic and there are two receptacula seminis. 
Family DUVAUCELIID^ (Tritootidje). 
The branchise consist of tufts set along the mantle-region or occasionally 
they may be absent altogether. 
G-enus SpHiJSROSTOMA Macgill. Hist. Moll. Anim. Aberdeen, etc. (1843). 
Type by monotypy : S.jamesonii Macgill. = T. hombergii Cuvier, 1803. 
T3'pe : S. liomhergii (Cuvier). 
Synonymy: Tkitonia Cuvier, Tabl. E14m. Hist. Nat. 1798, p. 387, auct. 
Necromantes Gistel, Natur. des Tierr. f. Schulen, 1848, p. xi. 
LiBiOPE Gistel, „ „ „ 1848, p. 171. 
The body is limaciform, but somewhat rectangular in outline, except at the 
end, where it tapers to a short tail. The foot is broad. Over the mouth is an 
oral veil bearing two grooved tentacles at the ends, and in the middle 
tubercles or processes. The rhinophores are retractile into raised sheaths ; 
they are not perfoliate, but surrounded by a few plumes. The dorsal margin is 
slightly prominent, and bears a single row of branchial tufts which are more 
or less arborescent. Anal and renal openings lie on the right side. The jaws 
are large, with several rows of denticles or prominences near the edge. The 
radula varies greatly in size in the different species, but always consists of a 
broadish central tooth with a moderate or large number of laterals which are 
usually simpl}' hamate. The first lateral is usually larger than the others, 
and somewhat clumsily shaped. The liver is not divided and sends off no 
branches to the gills. There is no armature either in the stomach or on the 
genitalia. The hermaphrodite gland forms a layer over the liver [Eliot). 
It will be noted that the name of the family is changed from Tritoniidse 
Cuvier, as this name is preoccupied, and Duvauceliidse substituted. Tritonia 
Cuvier being preoccupied has to l>e replaced by SjiJucrostovia Macgillivray, 
