Dr. S, Dowler on Vmparom Pish in Louisiand, iO§^ 



somewhat into a grayish-yellow round the thoracic fins, whicH 

 are nearly central between the dorsum and abdomen, being on 

 a level with the eyes, and about one line from the opercula. 



There are six or seven rows of scales. The spinous rays of 

 the fins are, about twenty-live caudal, twelve anal, fifteen dorsal, 

 ten thoracic. 



The foetuses are half an inch long, all alike, exactly resembling 

 the maternal form and proportion, with the following slight ex- 

 ceptions : namely, their bodies are more slender and compressed 

 laterally ; their heads are comparatively larger, and their eyes 

 more prominent; their colours are less variegated, and paler. 

 A still greater difference appears about the middle of the abdo- 

 men, where there is attached to each foetus a whitish, faintly 

 yellowish, placenta-like irregularly formed mass of considerable 

 size, having a broad base, being apparently implanted in or 

 blended with the abdominal integument, possessing considerable 

 strength, and constituting what may be termed the umbilical 

 prominence ; perhaps it may turn out upon further examination 

 that this mass may not be placental, but an adherent mesenterid 

 mass of convoluted membrane. 



These foetal fishes were probably sufficiently developed at the 

 time of the parentis death to live independent of the mother. 



The remarks of Br. Dowler upon a viviparous fish of Loui- 

 siana, contained in the above notice, add a few points to the 

 unpublished facts connected with the history of that family. 

 The fish itself is not new; it has already been described and 

 figured in 1821 by Lesueur, in the 2nd volume of the Journal 

 of the Academy of Natural Sciences in Philadelphia, under the 

 name of Pcecilia multilineata. It belongs to my family of 

 Cyprinodonts^ . I have had ample opportunity of observing 

 large numbers of this fish during my stay in the South, in the 

 spring of 1853, in Mobile and in New Orleans, where it is found 

 everywhere in the lagoons in the immediate vicinity of these two 

 cities, and not only of ascertaining that they are viviparous, 

 but also of tracing the whole development of the embryo from 

 the first stages of the segmentation of the yolk to the hatching 

 of the young, which were freed from the abdominal pouch of 

 the mother in the month of April. The date of the observations 

 of Dr. Dowler seems to show that they breed twice a-year. I 

 should have hastened to publish my investigations, had not 

 Duvernoy already published a very full account of the later 

 period of the embryonic growth of another species of this genus, 



* See Agassiz's Recherclies sur les Poissons fossiles, vol. v. pt. 2. p. i'J-^*"^ 

 Ann, ^ Mag, N, Hist. Ser. 2. Vol. xv. 14 



