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THE AMERICAN NATURALIST [Vol. XLIV 



particular microscopical examination of this "milk" was 

 made. These observations fully confirm those of Alcock 8 

 on Indian Ocean rays in the "Investigator" expeditions. 

 They are necessarily incomplete, but it is the purpose of 

 the writer to make a careful study of the phenomenon of 

 viviparity in sharks and rays. 



Lepisosteus osseus, the "shell gar" of the fishermen 

 (so called to distinguish it from the green gar, Tylosurus 

 marinus, formerly Belone longirostris), often comes down 

 from the swamps and upper reaches of Newport River 

 into the brackish water at and even below the Narrows. 



In 1908 my fishermen caught several at Cross Rock. 

 Of these, three were thrown on the grated bottom of the 

 gasoline launch, and, with no further attention than hav- 

 ing an occasional drenching with a bucket of salt water 

 and being covered from the sun's rays by the corner of 

 an old sail, were brought to the laboratory. Here they 

 were put in a large tank of fresh water, which was aerated 

 only semi-occasionally by a jet from a pet-cock. As a re- 

 sult of this severe experience, one of the fish died. How- 

 ever, the other two survived, though their pectoral and 

 caudal fins were badly split and were congested with 

 blood as a result of their threshing around on the floor 

 of the boat during the journey of more than an hour from 

 the fishing ground to the laboratory. Further, in a short 

 time the fins of the living fish became much worn by 

 contact with the scaling paint of the tank. 



These two gars came safely through the winter of 

 1908-09, thanks to the care given them by the laboratory 

 men under the direction of the superintendent of the sta- 

 tion, Mr. Henry D. Aller. On my return to Beaufort on 

 May 26, 1909, I found that the fish had completely re- 

 generated their fins and that these were in as good phys- 

 ical condition as the day, ten months before, when the 

 gars were taken out of the bunt of the seine. However, 

 the larger of the two had the body curved in a curious 

 very flat S, which led me to think that it had suffered 

 some injury resulting in deformity. On June 4 this crook 

 had disappeared and the fish seemed to be perfectly 



