Labyrinthici and Holconoti 277 
proaching about the back and on the fins a black color, and a 
remarkably vigorous fish. The young which I took from her 
were in shape, save as to rotundity, perfect miniatures of the 
mother, formed like her, and of the same general proportions, ° 
except that the old one was (probably owing to her pregnancy) 
much broader and wider between the top of the dorsal and the 
ventral fins in proportion to her length than the young were. 
As to color, they were in all respects like the mother, though the 
shades were many degrees lighter. Indeed, they were in all 
respects like their mother and like each other, the same pecu- 
liar mouth, the same position and shape of the fins, and the 
same eyes and gills, and there cannot remain in the mind of 
any one who sees the fish in the same state that I did a single 
doubt that these young were the offspring of the fish from whose 
body I took them, and that this species of fish gives birth to her 
young alive and perfectly formed, and adapted to seeking its own 
livelthood in the water. The number of young in the bag was 
nineteen (I fear I misstated the number in my former letter), 
and every one as brisk and lively and as much at home in a bucket 
of salt water as if they had been for months accustomed to the 
water. The male fish that was caught was not quite as large 
as the female, either in length or circumference, and altogether 
amore slim fish. I think we may reasonably expect to receive 
the specimens by the first of December. But I can hardly 
hope to get satisfactory specimens of the fish as I found it, with 
young well grown, before the return of the same season, viz., 
June. By that time I trust the facts will be fully decided, 
and the results, as important as they may be, fully appreciated.”’ 
Dr. Jackson’s specimens came from Sausalito Bay, near 
San Francisco. Soon after the publication of this letter a 
similar discovery was made independently by Dr. William P. 
Gibbons, of Alameda. Still other specimens were made known 
in 1854 by Dr. Charles Girard, these having been collected in 
connection with the United States Pacific Railroad Surveys. 
The species first examined by Dr. Jackson was named by Agassiz 
Embiotoca jacksont. 
In Professor Agassiz’s comments on Dr. Jackson’s discovery 
he makes the following observations (Amer. Jour. Science and 
Arts, 1854): 
