178 



Scientific Proceedings (60). 



keel on one or both margins. In some cases, nearly always in 

 other lots of eggs than those which developed into larva? having 

 definite tail-like accessory appendages, the accessory structure 

 was distinctly dorsal or cephalic in position. In some of the 

 cases the structure was merely a broad -based, blunt, fleshy pro- 

 tuberance; in others it was wholly epidermal, — a more or less 

 slender, sac-like epidermal projection. In still others the pro- 

 tuberance was longer, 1/8 to 1/10 the length of the larvae, and 

 extended distinctly forward from the frontal, dorso-frontal, or 

 ventro-frontal region of the head. In some of these cases the 

 myomere structure was evident although no fin-like margins 

 occurred and the structures were approximately round in cross 

 section. 



In certain cases in which early gastrula stages of Amby stoma 

 punctatum had been centrifuged, a number of the larvae lacked the 

 anterior region of the head including the eyes and, in fact, most of 

 the head anterior to the gill region. A single lot of eight larvae 

 contained five possessing this abnormality. 



Interpretations of these structures will be suggested in a larger 

 paper. 



109 (926) 



Further observations on the toxicity of tin. 



By William Salant and J. B. Rieger. 



[From the Pharmacological Laboratory of the Bureau of Chemistry, 

 Washington, D. C] 



In a preliminary communication 1 from this laboratory, the 

 results of experiments with the double salt of tin tartrate were 

 announced. Experiments performed since with tin tartrate have 

 shown that like the double salts, it caused marked injury to the 

 kidneys. Large amounts of albumin were present in the urine of 

 rabbits when administered subcutaneously and intravenously but 

 larger doses of the normal salt were required to produce this effect. 



The amount of tin as the double salt necessary to produce a 

 very marked albuminuria was 20 to 30 per cent less than in the 

 form of tin tartrate. Observations on the action of stannous and 



'Salant and Smith, J. Phartn. and Exp. They., 1914, Vol. 5, p. 517. 



