SALMONOIDS. 
829 
In the structure of the ovaries the Salmonoicl fam- 
ily stands almost alone among the Teleosts. Only 
among the Eels, in a New Zealand family ( Galaxiidce ) 
and an East Indian and West African family ( Notopter - 
idee), are the eggs deposited in the same manner. Yet 
the SaJinonoids cannot be said to be entirely destitute 
of oviducts. The true difference between the ovaries 
of this family and those of most other Teleosts is that, 
while in the latter the said organ is a closed sac, open 
only behind (through the oviduct), the outer wall of 
which is formed by a fold of the peritoneum (meso- 
arium), and round the inner surface of which the ovi- 
ferous layer is set in transverse or longitudinal folds 
(lamellae), in the Salmonoid family this layer extends 
only over the outer side (the side facing the lateral wall 
of the abdominal cavity) of the simple, pendent meso- 
arium (peritoneal fold). Or in other words, we may 
imagine the otherwise closed ovary (together with the 
oviduct) to be split throughout the length of the outer 
side (the side facing the lateral Avail of the abdominal 
cavity). Both at the anterior extremity of the ovary 
and at the loAver (ventral) margin, however, the meso- 
arium bends toAvards the outer side, and behind the ovary 
the mesoarium is continued in the form of a simple 
lamella, either hanging betAveen the intestine and the 
Avail of the abdominal cavity, Avith the loAver (ventral) 
margin free, or Avith the said margin curved upAvards 
and outwards and coalescent Avith the Avail of the ab- 
dominal cavity, thus forming an oviduct (abdominal 
funnel) open even in front. These oviducts (fig. 208) 
— one on each side in front, but united at the extreme 
end into a common passage behind the intestine — Avhich 
occur in the Smelts and Capelins, are indeed imperfect 
in comparison Avith those of the other Teleosts. But 
in their anterior opening they sIioav a remarkable ana- 
tomical resemblance" to the corresponding structure both 
in the Ganoids (Avith the exception of Lepidosteus ), 
Sturgeons, and Cartilaginous fishes and in the higher 
vertebrates, where the oviducts (Mullerian ducts) are 
separate from the ovaries and open into the abdominal 
cavity, receiving in this orifice the ripe eggs Avhen de- 
tached from the ovaries. 
Genus SALMO. 
Mouth armed with strong and pointed , rather scattered teeth , set in one row on the lower jaw, the inter maxillaries, 
the maxillaries , and the palatine hones, in one or two rows ( hut deciduous and sometimes wanting) on the shaft of 
the vomer, in an irregular group on the head of the vomer, in two rows on the tongue. Length of the maxillaries 
behind the intermaxillaries as a rule 53 — 63 % b , and of the lower jaw as a rule 75 — 95 % c , of that of the head 
from the hind extremity of the intermaxillary hone to the posterior margin of the preoperculum. Number of rays 
in the anal fin as a rule less than in the dorsal d and at most 14, of which 7 — 10 are branched, and the base 
of the anal fin shorter than that of the dorsal. Pyloric appendages well-developed and numerous ( about 25— -90). 
Scales small, more than 100 in the lateral line, which is complete. 
In the Tertiary Period, when the Rocky Mountains 
rose and divided the arctic and temperate Avaters of 
North America into tAVO regions, an eastern and a Avest- 
ern, the genus Salmo Avas differentiated in two distinct 
directions of development, of which in the above dia- 
gnosis Ave have taken into account only one, the Sal- 
mons and Charr of the eastern region. The other course 
of development ran side by side Avith this — branched 
like it into Salmon and Charr — but acquired a cha- 
racter peculiar to itself in the long anal fin, with a 
greater number of rays, (15?) 17 — 19, of Avhich 14 — 
16 may be branched. This direction of development, 
whether Ave choose to regard its forms as a genus or 
subgenus, has received in recent times 6 the name of 
Oncorhynchus. To the European faunist it is not Avith- 
out interest, for its best representative, the Quinnat 
° Cf. Rathke, Beitr. z. Gesch. d. Thierw., Abtli. 2. Uber den Darmkanal und die Zeugungsorgane der Fische , pp. 123 and 159; 
Huxr.EY, Proc. Zool. Soc. London 1883, p. 132; Weber, Morphol. Jahrb., XII, p. 3G6. Oviducts of the same description occur in the Cape- 
lin; but there only one (the left) ovary is fully developed. In Salmo and Coregonns the mesoarium passes over the rectum, forming on 
each side thereof a short abdominal funnel (peritoneal duct). 
h In Parr and individual exceptions 43 — -53 % or, on the other hand, up to 78 %. 
C (IK 7 PC -111 0 / 
?? 9? •)•> ) ?? ?? n ?> x x 
d Sometimes the number is the same. 
e Suckley, Ann. Lyc. Nat. Hist., New York 1861, p. 312. 
