1870.] DR. A. GUNTHER ON FROTOTROCTES. 151 
single example which was obtained for the British Museum in a col- 
lection of fishes sent from Victoria to the International Exhibition in 
1862 (Fish. v. p. 382). I then associated it with Haplochiton, a 
genus inhabiting cold fresh waters of Tierra del Fuego, of the Falk- 
land Islands, and of the southern parts of the South American con- 
tinent. The characters, as far as they could be observed, seemed to 
warrant the propriety of uniting the two genera into a family, Haplo- 
chitonide ; and for the new genus the name of Prototroctes (in 
allusion to its Salmonoid affinities) was proposed. A few days ago 
two perfect specimens of the latter genus, preserved in spirits, were 
submitted to my examination* ; and I am now enabled to complete 
the description of the generic characters, as well as to add a second 
species to the genus. 
These fishes have entirely the appearance of Coregonus. The body 
is covered with cycloid scales of moderate size ; the first dorsal short, 
immediately behind the middle of the length of the fish, and imme- 
diately behind the insertion of the ventral fins; adipose fin small, 
opposite to the end of the anal, which is not much longer than the 
dorsal. Caudal fin forked. The structure of the mouth is entirely 
different from that of Coregonus ; it is of moderate width, and cleft 
to below the eye ; the snout is pointed, with a mesial notch to receive 
the soft skinny end of the lower jaw ; the intermaxillary and maxillary 
are intimately attached to each other along their whole length, and 
the margin of the upper jaw is formed by the intermaxillary only. 
The upper jaw is provided with a series of minute teeth, slightly bent 
inwards, very similar to those of Mugil, not anchylosed to the bone, 
but imbedded in a cartilage with which the intermaxillary bone is 
covered. Lower jaw with a series of minute teeth, which are more 
distantly placed than those of the upper, and inserted in the bone 
itself: a layer of horny substance, such as is found in many Cyprinoids, 
intervenes between the upper and lower jaws, and is easily detached 
from the lower. Vomer and palatine bones with a single series of 
minute teeth ; tongue on each side with a series of small recurved 
teeth. Gills four. Pseudobranchie none. Branchiostegals six, 
short, broad, as in Coregonus. Air-bladder large, simple. Stomach 
eeecal, slightly more muscular in its cardiac and pyloric portions than 
in the middle. Pyloric appendages none. Intestinal tract of moderate 
length, one-half longer than the entire fish. Peritoneum of a deep 
black colour. Both our examples are unfortunately males, so that 
the condition of the ovaries and oviduct is still unknown: it seems 
that the testicle is developed on the left side only, where it forms a 
long, broad, and very thin lamina; a vas deferens connects this 
lamina with another smaller one situated in the hindmost part of the 
abdominal cavity. Urogenital orifice with a very small and short 
tube. 
It is evident from this description that the union of Haplochiton 
and Prototroctes in one family is perfectly justified, although the pre- 
* They were in the first instance (Nov. 1869) sent by the Westland Natural- 
ists’ Society of New Zealand to Mr. Buckland, who eventually requested me to 
give an opinion about them. 
