107 [Greeiileaf. 



25. Fragments of lumbar vertebrae ; 26. Carpal bone of unknown 

 animal; 27. A portion of the lower jaw, the teeth worn to the base 

 of the crowns, so that but little besides the fangs remains ; not de- 

 termined. 28. A fragment of a scapula of unknoM^n animal, includ- 

 ing the glenoid cavity. 29. Lower end of the thigh-bone of a masto- 

 don, of about the size of Mastodon giganteus. This probably be- 

 longed to the Mastodon Humboldtii. 30. Lower end of the radius of 

 a mastodon. 31. Fragment of the ilium of a mastodon. 



Mr. Andrew F. Hall donated a specimen of Lycopodiinn 

 lepidophyllum from Sonora, Mexico, which remained curled 

 up when dried, but retained its life indefinitely, expanding 

 when placed in water. He also presented a bulb of the 

 family Amaryllidacese, from California, the integuments of 

 which were cottony. 



Dr. J. C. White exhibited a human cranium, presented by 

 Mr. Curtis, for which the thanks of the Society were voted. 



Professor P. A. Chadbourne, of Williams College, was 

 elected a Corresponding Member; and the following gen- 

 tlemen Resident Members : Dr. N. S. Cressy, of Cam- 

 bridge, and Dr. Calvin Pratt, of Boston. 



The following paper was read before the Microscopic 

 Section, March 8th : 



On a new species of Nitzschia. By R. C. Greenleaf. 



NiTZSCHIA MITCHELLIANA. nOV. Sp. 



^^ 



\i4lll|ii'|i'lTli|il[77r^M^TpTTTfrTiTTTTT17T^ 



Valve linear lanceolate, arcuate on the dorsal margin, apices curved 

 into a beak-like form, strite very faint. From the dorsal margin proceed 

 costse of unequal length, the largest reaching almost to the middle of 

 the valve. Length of longest valve, .0055. 



I have examined several specimens of this species, all having the 

 same peculiarities, but have failed of finding a front view. It belongs 

 to the group of N. amphioxys and N. vivax. 



I have named this diatom in compliment to my friend, Henry 

 IMitchell, Esq., of the United States Coast Survey, to whom I am 



