552 ICHTHYOLOGY. 



but the actual capacity of the stomach.* Some, as the Trout, 

 act the part of tyrants over their fellows. 



Fishes are almost incredibly prolific. One species, the Blenny, 

 produces its young alive, sometimes two or three hundred at a 

 time, and able to provide for their own support. A species of 

 viviparous fish, but two inches in length, inclusive of the caudal 

 fin, and containing twenty-two perfect fish, has also been found 

 in a canal connecting with Lake Pontchartrain. Larger speci- 

 mens have been received by Agassiz from Lake Erie, and also 

 from California. But, generally, the continuation of the race is 

 accomplished by means of eggs, called, in the aggregate, spawn ; 

 and before exclusion, roe. The eggs are deposited in various 

 places, on sticks, stones, grass, furrows in the sand, etc. In rare 

 cases, as the Goby of the Mediterranean, some North Amer- 

 ican Cyprinida or Carps, and the HASSARS, Callichthys, of Dem- 

 erara, a nest for the reception of the spawn is built, consisting 

 of a single pile of stones, or else, as in the last named fishes, a 

 more complicated structure of grass and sticks. The Stickle- 

 back, (Gasterosteus,) forms of sea- weed and common coralline, 

 pear-shaped nests, which hang from the rocks, variously inter- 

 mingled with each other. The Shark, instead of depositing 

 almost innumerable eggs in a season, like the Cod or the Her- 

 ring, produces two eggs, of a square or oblong form, (see fig. on 

 Chart,) the coat of which is composed of a tough, horny and 

 semi-transparent case ; each corner is prolonged into a tendril, 

 of which the two which are next to the tail of the enclosed fish, 

 are stronger and more prehensile than the other pair. The 

 use of these tendrils appears to be their entanglement among the 

 stalks of sea-weeds, and the consequent mooring of the egg in a 

 situation of protection and comparative security. The part of the 

 skin near the head, is weaker and more easily broken than any 

 other part, a provision for the easy exclusion of the animal, 

 which occurs before the entire absorption of the yolk of the 

 egg, the remainder being attached to the body of the young 

 fish, enclosed in a capsule, which for a while it carries about. 

 The position of the animal while within the egg, is, with the 

 head, doubled back towards the tail, one very unfavorable for 

 the process of breathing by internal gills. But as a provision 



* "At a lecture delivered before the Zoological Society of Dublin, Dr. 

 Houston exhibited, as ' a fair sample of a fish's breakfast,' a Frog-fish two 

 feet and a half long, in the stomach of which was a Cod-fish, two feet in 

 length ; the Cod's stomach contained the bodies of two Whitings of ordi- 

 nary size ; and the Whitings, in their turn, held the half digested remains of 

 many smaller fishes, too much broken up to be identified." 



