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 narrovi^-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 uterine 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 



