1887.] natural sciences of philadelphia. 115 



April 5. 



Rev. Henry C. McCook, D. D. in the chair. 



Forty-four persons present. 



Papers under the following titles were presented for publication: 



"The Terrestrial Mollusca inhabiting the Samoa or Navigator 

 Islands." By Andrew Garrett. 



"Notes on Fresh-water Rhizopods of Swatow, China." By Adele 

 M. Fielde. 



Note on the Multiplication of Disioma. A note was read from 

 Miss Adele M. Fielde, dated Swatow, China, Feb., 1887, to the 

 effect that Distoma infests a species of snail found in many of the pools 

 and wells near Swatow which is eaten, boiled, by the Chinese, and 

 which is fed raw to ducks and geese. On dissecting, recently, an 

 apparently healthy specimen, having a shell an inch long, she had 

 found its liver almost wholly replaced by a Redia, the parent of the 

 Cercaria, which being passively transferred to the alimentary canal 

 of a vertebrate, develops into the Distoma. The life history of this 

 trematode, as worked out by A. P. Thomas, is given in the Quarterly 

 Journal of Microscopical Science, 1883, pp. 99-133, and Limnceus 

 is mentioned as its host. 



The Redice seen in the snails were of an orange yellow 

 color and the largest were one-tenth of an inch in length. 

 There were counted two hundred and fifty-three that were large enough 

 to be easily isolated by the use of a needle point under the naked 

 eye ; and scores more, of smaller size and paler yellow, were visible 

 under a lens. On 02:)ening several of the larger Redioi, whose mus- 

 cular mouths were active; they were found each to contain from 

 eighteen to twenty-six Cercarice, strong enough to whirl their tails 

 vigorously, beside many embryos less fully developed. The Cer- 

 carice. moved rapidly over a glass slide by the use of their two 

 suckers ; and, merged in water, retained their vitality for thirty 

 hours after being removed from the snail and the Redia. The one 

 snail must have been the host of at least ten thousand larval 

 Distomas. 



April 12. 

 Mr. Charles P. Perot in the chair. 



Thirty-one persons present. 



The Placentation of the Two-toed Ant-eater, Cydoturus didactylus. 

 -Prof J. A. Ryder remarked that some months since Mr. J. W. 



