NO. 2291. MAMMALIAN AND FISH REMAINS FROM FLORIDA—HAY. 1 1 1 



Levy County, Florida. This place is near the present town of 

 Williston. These gar remains are doubtless those mentioned by 

 Leidy in 1896.* An examination of these shows that they belonged 

 to a fish closely related to that known as alligator gar, usually called 

 Lepisosteus tristoechus. However, this gar appears to the writer to 

 be generically distinct from the long-snouted gar and hence to be 

 called Atractosteus Rafinesque. The fossil materials from Williston 

 are referred to this genus and may be known as Atractosteus lapi- 

 dosus. The opercular bone is made the special type of this species. 

 It can hardly be doubted that the scales belonged to the same in- 

 dividual fish. In case the opercular bone had the same length, 

 proportioned to the remainder of the body, as in a specimen of A 

 tristoechus the total length of the fish was close to 27 inches. 



The opercular is represented of the natural size by figure 4 of plate 

 26. The height near the front border is 26.5 mm. ; the length is 24 mm. 

 The corresponding dimensions of this bone in a specimen of the 

 existing alhgator gar are 54 mm. and 54 mm. This bone also is 

 shown, reduced to the same size for comparison (pi. 26, fig. 5). It 

 belonged to the left side of the head. The fossil bone is entire, ex- 

 cept that a small fragment is missing, the loss of which has pro- 

 duced the notch in the lower border. It will be seen that there are 

 some differences in the shape of the two bones. The greatest differ- 

 ence is found, however, in the character of the sculpture. That of 

 the fossil differs in consisting of more regular, more continuous, and 

 more sharply defined ridges descending from the upper angle of the 

 bone. The ridges of the existing fish consist of a sort of network 

 of low ridges, especially on the front half of the bone. Also the 

 ridges of the front half are directed do\vnward or downward and 

 backward, while in the fossil they turn somewhat forward in their 

 descent. In the existing fish the ridges of the front half are more 

 widely separated than those in the hinder part; in the fossil they 

 are narrower and more closely packed. 



Ten of the scales are here represented of the size of nature (pi. 28, 

 fig. 8). It will be seen that some of them have the upper hinder 

 border toothed, while others have this border smooth. In these 

 respects they resemble the scales of the existing alligator gar (pi. 

 28, fig. 9) except that there appear to be fewer of the teeth. Both 

 Lepisosteus osse,us and L. platystomus have the borders of all the 

 scales smooth; at least the wiiter has not found toothed scales in 

 either of these species. 



* Trans. Wagner Free Inst. Sci., vol. 4, page x. 



