ZOOLOGY OF THE VOYAGE 1 3 2 OF THE BEAGLE.
the adipose, or perhaps a trifle beyond it ; two small spines at its commencement ; the first two
soft rays simple, the others branched. Caudal forked for half its length, the lobes equal; the whole
fin contained about six and a half times in the entire length ; the accessory rays very numerous,
and partially fringing the upper and lower edges of the tail. Pectorals attached behind the
gill-opcning, rather below the middle, about two-thirds the length of the head, of a somewhat
triangular form, the rays gradually shortening from the first, which is the only one unbranched.
Ventrals attached a very little in advance o f the dorsal, rounded, or almost cut square at the
ends, the rays being all nearly equal. They are scarcely shorter than the pectorals : the space
between their insertion and the commencement of the anal is nearly double their own length.
There is no long scale or appendage o f any kind in their axillæ.
Colour.— “ D ull leaden colour.”— D ,— In spirits it appears brown. T he sides are banded with
some irregular transverse zebra-like marks, not noticed by Mr. Darwin, reaching from the
back down two-thirds or three-fourths o f the depth, some terminating sooner than others. All
the fins brownish.
Habitat, Falkland Islands.
Mr. Darwin obtained three specimens of this remarkable fish all precisely
similar, from a fresh-water lake in the Falkland Islands, in March. The lake
was not far from the sea, and connected with it by a brook. He adds in his notes
that the species is common there ; that it is good eating, and grows to be about
half as large again as the individuals procured.
One of these specimens was dissected by Mr. Yarrell and myself, and presented
the following internal characters, which are of importance to be noted.
The coats of the stomach were thick and muscular; the oesophageal portion with
prominent longitudinal plicæ. Its contents, so far as they could be ascertained,
consisted of the remains of caddis-worms. The intestine was large, without any
coecal appendages, but with one spiral convolution at the end of the first third of
its length from the pyloric orifice : the entire length of the canal was four inches.
The air-bladder was large, undivided, and of the same general form as in many
of the Salmonidæ. There were two elongated flattened lobes of roe nearly ready
for exclusion. The anal and sexual orifices were separated, but enclosed in a
tubular sheath, common to both, directed backwards; the sheath itself lying in a
groove m the abdomen, and five-eighths of an inch in length : tlie opening to the
cavity of the abdomen and sexual organs was at the extreme end of this sheath,
and partly closed by two lateral valves ; the opening to the intestine, three-eighths
of an inch short of the extremity.
2 . A p l o c h i t o n t æ n i a t u s . Jen.
P tiijs X X IV . F io. 2.
A . olmacem, punctis fuscis minutissimis irroratus; lateribus viltà longitudinali ar-
gentea : maxilla inferiore longiore.
B. 3 ; D. 1 2 ; A. 2/13; C. 16, &c. ; P. 18 ; V. 7.
L o n g . unc. 3. lin. 10.
F orm.—A much smaller species than the last, but the general form similar. B ather more elongated,
the depth being contained seven and a half times in the length. H ead one-fifth o f the
length measured to the base of the caudal fork. Snout a little longer, and more pointed.
Low er jaw at all times a little the longest. T eeth similar, and similarly disposed. ^ Nostrils
sim ilar; but no pores on the crown, or only one on each side, and that not very distinct. All
the fins similar.
C olour.— N ot noticed in the recent state. In spirits it appears of a uniform greenish or olivaceous
brown, the back and sides very minutely dotted with darker brown. There is a pale silver
band along the middle of the side, not bounded, however, by any definable line, h n t shading
off insensibly into the brown above and below. T he hides are still bright, and appear to have
been golden.
Habitat, Goree Sound, Tierra del Fuego.
There are three specimens of this second species in the collection, all of the
same size, and not differing in any respect from each other, except that one of
them has thirteen rays in the dorsal fin, and fourteen soft rays in the anal. Mr.
Darwin’s notes state that they were taken at Goree Sound, Tierra del Fuego, in
the mouth of a fresh-water stream, where the water was quite fresh ; and that
when put into salt water they immediately died.
The silver band at once distinguishes this elegant species from the last, independently
of its smaller size. The specimens appear full grown.
There is the same peculiarity with respect to the anal and sexual orifices in
this species, as in the one previously described.
F a m i l y .— C LUPEID® .
1. C l u p e a F u e g e n s is . Jen.
Mr. Darwin’s collection contains a single individual of a species of Clupea
from Tierra del Fuego so extremely similar to the young of the common Herring,
that it might almost be mistaken for it. As it is small, and in not very good
preservation, I shall merely point out some of its leading characters.
D epth of tho body the some as in a young H a rin g of the same size. Belly carinated, but with the
serratures not more developed than in that species. T eeth the same, and very m inute. The
maxillary does not slope inwards quite so much at its upper extremity, before uniting with the
interm axillary; h u t the mouth and its several parts are in all other respects similar. The
same may bc'said of the pieces of the opercle. excepting that there is a more sensible notch
f t.1h e upper par,t o/■f- -t-h--e- --p-o--s-t-e--r-i-o--r- --m---a-r--g:i—n oTf the rgwilUl-i-ffll;orv much as Id the common It