45 



No. 3 shows arrangement of stellate colonies of D. ruede- 

 inatini on the sea floor. 



In the center of the colonial stock a "funicle" (cf Nos. 14, 

 49, 50) can be observed. The funicle is a stem which connects 

 the bases of the stipes and is enclosed in a chitinous capsule, the 

 " central disk," which again is attached to a larger organ, the 

 " basal cjst." The latter appears sometimes as a square plate. 



Nos. 4-12 show the central pai'ts. 



The central disc has been found to be sometimes surrounded 

 by a whorl of chitinous sacs, which in a few instances have been 

 observed to contain siculse, and, therefore, have been termed 

 " gonangia." 



No. 13 shows a " gonangium " with enclosed siculje. 



Nos. 14-19 exhibit "gonangia" as whorls of mostly four 

 chitinous plates. 



No. 20 shows a colony from which the crowd of siculaj around 

 it has been discharged. Some of the sicula; remained undetached 

 and developed into new stipes, the sicula; becoming the most 

 distant part of the stipe. 



Nos. 21, 39, 44 show examples of undetached siculce. 



Detached sicula;, Nos. 22-25, possess a basal appendage which 

 appears in the fossil state as a subquadratic plate with a central 

 node from which proceeds the " caulis" of the sicula. 



The detached siculse developed, by budding of theca, into a 

 "stipe" or " rhabdosome," the primary stipe of a new colonA^ 

 Equal-aged stages of the growing stipes are mostly found ag- 

 gregated together, as seen in No. 26. 



Nos. 27-36 are successive growth-stages of the primary stipe, 

 which illustrate the growth from a stipe with one theca (No. 27) 

 to one with nine thecae. On most of the specimens the basal 

 appendage is also discernible. 



After the primary stipe had reached a certain size the first 

 generation of gonangia developed on the basal appendage. 

 Many of the sicula;, generated in these, remained attached to 

 the parent colony and formed a whorl of secondary stipes, by 

 which the colony assumed the stellate appearance. 



Nos 37 and 38, young colonies with the first generation of 

 gonangia and siculse. 



Nos. 39-42, colonies of siculse. 



No. 43, central disk with only four siculae. 



Nos. 44 and 22, more advanced colonies with siculie in the 

 center. 



No. 45, young colony with primary stipe. 



Nos. 46-48 show development of siculae into secondary stipes. 



No. 49 exhibits a young colony with a distinct funicle and 

 No. 50 one with funicle and central disk. 



No. 51 is a colony which distinctly exhibits two generations 

 of stipes (No. I shows three generations). 



No. 52 is a slab covered with the broken stipes of D. ruede- 

 manni. This is the common mode of occurrence of this fossil. 



A parallel arrangement of the fossils indicating a flow of 

 water, is noticeable on all slabs with fragments of stipes. (See 

 Amer. Geol., June, 1896.) 



