HAHN, DICTYONEMA-FAVNA OF NAVY ISLAND, N. B. 149 



In this connection several observations seem noteworthy. 



1. Number of basal organs: var. conferta 2, var. ruedemanni and 

 ruedemanni m. f. acadica 6, acadica juv. 2. 



2. At least one neanastic specimen of var. ruedemanni, 10 mm. long, 

 shows clearly a perfect stipe with a fringed, attaching expansion at the 

 base. 



3. Nema and stolon-like stem have the same structure. They grad- 

 ually increase from .1 to .6 mm. in width and are traversed by a central 

 canal. 



4. Disks may be expanded from the nema, the stolon-like stem or 

 immediately from the sicula. 



5. When basal stipes are present, the siculas are rarely kept distinct. 



6. Budding from stolons is not an unlikely occurrence. 



A few detailed observations may give confirmatory evidence. As to 

 point 6, a young individual of var. conferta (11 mm. in length) has 

 attached to the top of its sicula a small body .5 mm. in length, from 

 which an irregularly fringed stem rises in the opposite direction, while 

 "to the left denticulated processes depart. I consider it quite possible 

 that these denticles mark newly appearing thecae which budded from the 

 stolon-like stipe, as in the case of Wiman's Dictyonema cavernosum; 

 out the unfavorable kind of preservation as well as the singularity of the 

 specimen fail to furnish sufficient certainty of this explanation (see plate 

 XXI, 1&). 



Figs. 3& and 4a 7 on plate XXI are the types of Matthew (1895) which 

 belong to the variety ruedemanni and are crowded on the same surface 

 with 16 other Dictyonemas. Only four of them have distinct proximal 

 parts, one a simple sicula, one (see fig. 4a) exhibits a relatively thick 

 stem clistally broken off, the other "rootlets," the distal portions of which 

 are not quite evident. Siculse are lacking, apparently from being over- 

 grown by the mass of the stem. 



The individuals of figs. 3a, 4& can be explained as provided with true 

 floating organs. The specimen of figure 4c is excellently preserved, there- 

 fore of particular importance. 



Xow, Euedemann, though fully discussing the great probability or, as 

 I think, necessity of the suggestion of a true sessile life in the later 

 Dendroidea, objects ((1), p. 579) that "no cases of actual attachment 

 and fixation have yet been recorded." Hence, I searched among modern 

 benthonic forms provided with similar organs for attachment and be- 

 lieved I had succeeded, when I visited the excellent collection of the 

 Smithsonian Institution at Washington. On the Gorgonias there ex- 

 hibited, exactly the same kind of stems, partly stout and short, partly 



