Dr. B. Dowler on Viviparous Fish in Louisiana. 207 



several foetal fish enveloped in a delicate membrane. The parent 

 fish, which had been rudely thrust into a parrow-mouthed phial 

 of spirits, retains, after immersion for two weeks, the original 

 riffor mortis, and the same remark applies to the foetuses, though 

 they have been soaked in water : some of them have been forcibly 

 straightened. On the 17th of October, in the presence of, and 

 assisted by Drs. J. Hale and M. M. Dowler, I enlarged the 

 wound and proceeded to dissect a somewhat globular mass of 

 foetuses bounded by the intestines before, and separated from 

 them by an indescribably thin, diaphanous membrane; this 

 mass was further bounded above by the spine and ribs, below and 

 behind by the posterior inferior abdominal walls, bulging back- 

 ward of the anal orifice and fin. The exterior envelope of this 

 oblong globe consisted of a very thin, pellucid, extremely delicate 

 and apparently laminated and flocculent membrane, like the 

 amnion of the human embryo in the early state ; it did not form 

 a simple sac, but consisted of many duplications, like the arach- 

 noidal reflections among the sinuosities and convolutions of the 

 human brain, sending its prolongations as the hyaloid membrane 

 does through the vitreous mass of the eye. 



This utei*ine membrane (ovisac it cannot be termed) con- 

 tained twenty-two fishes. It is probable that the inner surface 

 of the uterine membrane sent forth a still more delicate mem- 

 brane which enveloped each fish after the manner that the peri- 

 toneum envelopes the abdominal viscera ; but the parent fish, 

 and still more its enclosed organs, were too minute to admit of 

 full demonstration during a necessarily hurried examination; 

 moreover, the wish not to mutilate the parent fish very much, 

 prevented a fuller dissection of the foetal mass in situ. 



Each foetal fish was doubled laterally, sometimes to the right, 

 sometimes to the left, into a globular form : the caudal fin, 

 which is inclined to the lancet shape, though blunter, overlapped 

 one eye and one side of the mouth : each fish in situ, and even 

 after forcible extraction from its bed, was enfolded in a sac ; 

 some were drawn out united by pedicles to a common stem, 

 somewhat like an umbilical cord. 



These foetal fishes presented a perfect example of close pack- 

 ing. A perceptible force was required to dislodge them from 

 their beds. The concavity left by their extraction appeared to 

 be lined with a smooth, black, peritoneal membrane. 



The intestines, which were very minute, were crowded forward 

 by the rounded mass of foetuses which occupied the greater por- 

 tion of the abdominal cavity. No ova were discovered. 



Without attempting fully to describe even the dermal skeleton, 

 I may observe, that this tiny fish is a most symmetrical one. 

 Its minuteness may be imagined when I state, that after the 



