220 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



A paper explaining the laboratory method of teaching paleobotany ui 

 Brown University was then delivered by the author, who illustrated he! 

 ]'emarks with copies of a laboratory manual prepared by her for the 

 purpose and distributed among the members. 



NOTES ON THE TEACHING OF PALEOBOTANY 

 BY MARION D. WESTON ^ 



A study of the growth of the arms in the cystid genus Caryocrinites, 

 illustrated by lantern slides, was then presented by the author under the 

 title 



METHOD OF APPEARANCE OF ADDITIONAL ARMS ON INCREASING AGE IN 



CARYOCRINITES 



BY A. F. FOERSTE 



{Abstract) 



The youngest known specimens of Caryocrinites ornatus Say from the 

 Rochester shale of New York possess three subtegminal food grooves, each 

 terminating in a single arm. Older specimens may possess 14 or more well 

 developed biserial arms at the ends of a corresponding number of branches 

 of the subtegminal food groove system. From this it is evident that the food 

 grooves branch within the theca, beneath the tegmen, and that there is some 

 method by which the food grooves pass through the theca and reach the 

 surface. On examining each articulating surface at which an arm was at- 

 tached to the theca, this is found to rest on three small plates at the margin 

 of the tegmen, the passage for the food groove being at the junction of the 

 three plates. A second passage, much smaller in size and apparently repre- 

 senting the axial canal, is located a short distance farther down, between 

 the two lower plates forming the articulating surface. 



Few specimens retain the arms. Usually only the articulating surfaces 

 for their attachment are observed. 



In addition to the articulating surfaces for the attachment of the arms, 

 practically all specimens, both old and young, possess small depressions in 

 their immediate vicinity. At the base of each of these depressions there is a 

 small passage located between two of the marginal plates of the tegmen and 

 connecting with the food-groove system. The larger of these depressions fre- 

 quently are marked along the median line by a single low ridge, arranged in a 

 radial direction and suggesting the former attachment here of some small 

 arm or armlike appendage. The smaller depressions show no evidence of 

 articulation with anything. 



The earlier of these depressions usually appear in accordance with a readily 

 recognized system. In the youngest known specimens, with only three distinct 

 arms, one depression makes its appearance on the sinistral side of each of 



1 Introduced by R. S. Bassler. 



