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BULLETIN OF THE UNITED STATES FISH COMMISSION. 
TYPES OF VIVIPARITY IN TELEOSTS. 
At least two types of viviparity may be distinguished in fishes : first, those in 
which the yolk furnishes all the intraovarian food ( Pcecilia ,* * * § Gambusia, Scorpcenidcef ) ; 
and second, those in which the greater part of the food is furnished by the ovary 
( Blennius , $ Anableps , § and JEmbiotocidce). 
In the first type the number of young is usually not less than in related oviparous 
forms, while the number of young in the second is always greatly reduced. 
In the largest of the Scorpcenidce, Sebastomus lev is, which reaches a weight of 
about 30 pounds, the ripe eggs, about 1 mm. in diameter, would fill several quarts 
since each of these develops into a larva before it is freed from the ovary, the max- 
imum number of living young produced by this class of viviparity reaches many 
thousands. Stuhlmann in 1887 recorded 405 young for Zoarces ; this he considered a 
remarkable number. 
The size and comparative development of the young of this class of fishes at the 
time of birth is of course much less than in the second class of viviparous fishes. 
The number of young observed in different species of viviparous fishes is as fol- 
lows: Sebastomus , many thousands; Sebastes marinus {fide Eyder), 1,000; Gambusia 
patruelis ( fide Eyder), 20 to 25; Anableps gronovii {fide Wyman), mother 7 inches long, 
with 4 to 5; 10 inches long, 18; 10 inches long, 7, each about 2^ inches long. 
JEmbiotocidce . — The number of young in any species varies greatly with the age of 
the parent: Hysterocarpus traski , 16; Hyperprosopon argenteus, 7 to 12 (Dec. 17); 
Hypsurus caryi, 8 ; Ditremci jacksoni , 8 || to 60; Phanerodon lateralis, 21 to 80; Phan- 
erodon furcatus, 10 to 23; Amphistichus argenteus , 47 to 80. 
* In Pcecilia (Duvernoy, 1844) and in Gambusia (Ryder, 1885) the egg is fertilized and the embryos 
remain in the original ovarian follicle till near the close of gestation. 
tin the Scorpcenidce (Ryder, 1886; Eigenmann & Eigenmann, Proc. U. S. Nat. Mns. 1892) the fol- 
licle is ruptured before impregnation takes place, hut the egg remains mechanically inclosed within 
it, and the blood supply of the follicles is continued till near the end of gestation. The term of ges- 
tation in Sebastichthys ( rubrovinctus ) lasts perhaps little over two months. 
tin Blennius (Rathke, 1883; Stuhlman, 1887) the. egg is impregnated while still in the follicle, in 
which it undergoes the early stages of its development. At the end of three weeks it is freed; the 
embryos remain three months longer in the ovary. The food supply seems to be furnished through 
the old follicles, and this method is but an extension of that found in Sebastes and its relatives. 
§ In Anableps (Wyman, 1850), whose early stages have not been observed, the larvae are sur- 
rounded by a vascular membrane, which is connected with the ovarian wall, even in embryos an inch 
long. The stages before the absorption of the yolk have not been observed. The yolk bag increases 
in size and is provided externally with a series of papillsB. 
A very moderate estimate would be 2 quarts. 
||The small number of young in Agassiz’s specimens was probably due to the lateness of the 
season, a time when only small individuals are still with young. 
