NEW YORK STATE MUSEUM 



increase in length toward the distal parts of the hydro- 

 some. That these very long stem-internodes, e.g. CI , 

 f 1 e x i 1 i s and CI. r i g i d u s , actually always consist of but 

 one theca, as the increasing length of the stem thecae in fig. 12 



<~ Fig. 12 Clonograptus (Goniograptus) sp. nov. Possesses long stem internodes, each 

 consisting of but one theca. x2J^ 



would suggest, the writer is not prepared to assert. As the 

 stems of these forms, in conformity with Hall's fundamental 

 views, have been currently considered as entirely indenticulate 

 or free from thecae, they have not been investigated as to their 

 structure, and conclusive data on the number of thecae in each 

 internode are not to be obtained in the literature. HalFs posi- 

 tion 1 was this : 



Neither the central portion, nor any of its subdivisions, 

 becomes celluliferous; and these parts are not termed stipes 

 or branches, according to the views I have entertained. It is 

 only beyond the last subdivisions of this part of the body, as in 

 G. 1 o g a n i , that the celluliferous parts, or the true stipes, 

 commence. 



Miss Elles 2 states that she has observed thecae on stipes of 

 every order in Clonograptus flexilis. Of special in- 

 terest in this connection appear to be the description and illus- 



1 Can. org. rem. Decade 2. 1865. p. 20. 



2 Quar. jour. geol. soc. 1898. 54: 473. 



