184 PROCEEDINGS OF THE AMERICAN ACADEMY 



seen in eggs of turtles, rabbits, squirrels, &c. The eggs of 

 Mammals are very minute, and surrounded by epithelium ; 

 and they begin at once their subdivision within the parent. 

 In those of birds, a large bulk of vitellus is developed in the 

 ovary, and afterwards the albumen and shell are added. The 

 same is the case in turtles, lizards, and serpents ; but the 

 eggs of Batrachians are different, and are small, elastic, and 

 dilatable, like those of fishes. He thought, therefore, that 

 there was a closer affinity between the first-mentioned reptiles 

 and birds than between them and the Batrachians ; and that 

 the turtles, lizards, and serpents might be incorporated with 

 birds, while the Batrachians were classed with fishes. 



Professor Horsford exhibited several specimens of vermilion 

 which varied very essentially in color from adulteration. 

 Some of the articles used for that purpose are chromate of 

 lead, sulphate of lime, and carbonate of magnesia. 



Mr. Desor mentioned some facts relating to the distribution 

 of animals in the region of Lake Superior, and specified some 

 of the animals found on Isle Royale, whose presence he was 

 at a loss to account for, except on the supposition that the 

 island was once continuous with the continent. 



Three hundred and twenty-sixth meeting. 



January 8, 1850. — Monthly Meeting. 



The President in the chair. 



Dr. C. T. Jackson, from the committee raised at a former 

 meeting to suggest a practicable mode for recording by coast- 

 marks the present mean sea-level on the Atlantic shore of this 

 country, made a report, in the form of a memorial to the 

 Secretary of the Treasury. The draft was recommitted, in 

 order that a proper resolution, expressing the sense of the 

 Academy, might be appended. 



Mr. Paine presented a communication from Professor Augus- 

 tus W. Smith, of Middletown, Connecticut, containing 



