Putuam.] 240 



Dr. C. T. Jackson exhibited an additional Emery mineral, 

 Diaspliore^ fi-om Chester, Mass., which was first identified by- 

 Prof. U. T. Shepard of Amherst College. 



Dr. Penio exhibited drawings of a gland-like body, situated 

 on the right thigh of a negro, aged 40 years, hving at Charles- 

 ton, S. C. This gland was situated over the "tensor vaginae 

 femoris" muscle, and in feeling and consistence, size and aj)- 

 pearance, together with the nipple, the centre of which was 

 depressed, strongly resembled the female mamma. 



Dr. B. G. Wilder made some additional observations on the 

 habits of the young, while in confinement, of Nephila plu- 

 raipes. 



Mr. A. Agassiz made a communication on the develoj^ment 

 of Limidus. and exhibited drawings of the young. 



Mr. Putman made some remarks on the ichthyological 

 fauna of the Great Lakes, as exhibited by the collection of 

 fishes which he had recently made at Lake Erie, and which 

 confirmed his previously expressed opinion that there was 

 only one flmna in the Great Lakes, and that Lake Cham- 

 jDlain belonged to it. At a future time he should offer a j^a- 

 per embodying the results of his investigations. 



He also exhibited specimens of the Whitefish of the 

 Lakes ( C or eg onus) ^ and remarked upon the great variability 

 of the species. He had had an opj^ortunity of examining 

 several thousand fresh specimens and was surprised to see the 

 marked differences in form and proportion between young 

 and adult indi\iduals, males and females, and even of individ- 

 uals of the same age and sex. In another species of the ge- 

 nus, called "Herring" at Lake Erie, this individual variation 

 was considerable, but still not so great as in the Whitefish. 



He said that the number of Whitefish had not appar- 

 ently diminished in that part of the Lake where he had been 

 (Kelly's Island), though for several years past thousands had 

 been taken each year. This he had reason to think was 

 due to the mode of fishing for them in "pounds," from which 

 the smaller specimens were enabled to escape, and owing to the 

 large number crowded together, the spawn and milt was 

 pressed out, and the eggs falling through the interstices of the 

 net were impregnated and developed. 



