HAHN, DICTYONEHA-FAUNA OF NAVY ISLAND, N. B. 139, 



Var. norwegica Kjerulf. 

 Apotypes : 

 (7) 1865. Kjerulf, p. 2, fig. 4 (1-3). 

 (2) 1906. Mobekg, pi. 1, fig. 7. 



(4) 1909. Westergard, pi. 30, figs. 8, 9. 



Description: After Brogger ( (5), p. 36), thick cross-threads, close network; 

 small, short, rounded meshes. 



I observed only 15 thecse. Young stages like var. acadica. Crossings 

 of all kinds into true acadica occur. A slight distinction between my 

 specimens and the Swedish ones is in so far recognizable as the first are 

 furnished with a little more elongated meshes, but they can be precisely 

 compared with Westergard's figures. My largest colony is 40 by 40 mm., 

 while Westergard cited a specimen 115 by 30 mm. in size. 



Var. ruedemanni 110m. nov. 

 Typical figures : 

 (1) 1904. R. Rtjedemann, pi. 1, figs. 16-20, 22 (12-15, non fig. 21). 

 Apotypes : 

 (10) 1895. G. F. Matthew, Trans. N. Y. Acad. Sci., Vol. 14, pi. 49, figs. 1, 2. 

 (The figures are not quite correct, showing a too open tissue.) 



Compare 



(5) 1882. Brogger, pi. 12, fig. 19. 



Description : In nepiastic stage strongly branching at an almost acute angle. 

 Full-grown specimens with crowded, more or less parallel branches up to 14 in 

 10 mm. width. Dissepiments appearing early, but afterwards irregularly scat- 

 tered. Thecal small, not much projecting. Adhesion organs relatively common. 



Notes: Generally funnelform, sometimes of intermediate shape (pyriform) 

 towards the vasiform variety "conferta." Measurement of a typical pyriform 

 specimen : 



Length Width in mm. 

 10 10 



20 25 



25 35 



48 65 



The specimens obtained from Navy Island (1ST. B.) fully agree with 

 Ruedemann's figures, but several specimens considerably surpass the 

 given characters in the same direction. In Europe it is rare, but abun- 

 dant in America, at Navy Island as well as at Schaghticoke. Largest 

 measured colony 165 mm. in length and 140 mm. in width. 



Var. desmograptoidea var. nov. 



Description : Infundibuliform. Open meshwork of irregular, mostly sub- 

 oval fenestrules. Branches undulating and sometimes coalescent. Dissepi- 



