Howe : Phvcological studies 577 



from lack of material, Count Solms expresses the hope " that this 

 remarkable plant will be found again soon." 



On November 11, 1902, the writer found on the northeastern 

 shore of the island of Key West, a considerable quantity of a hand- 

 some little Acetabulum growing attached to shells, stones, broken 

 pieces of coral, etc., at just about the low-water line and rather 

 closely confined to this zone. Adjacent, in water that was from 1 

 to 10 dm. deep at low tide, and occasionally approaching and inter- 

 mingling with the lower-growing individuals of this small green 

 Acetabulum, were numerous clusters of the larger, whiter, more 

 rigid, and more strongly calcified Acetabulum crenulatum (Lamour.) 

 Kuntze. A hand-lens showed the strong cusp or apiculum with 

 which each ray of the disc in A. crenulatum always terminates in 

 in the younger stages at least, while the rays in the smaller species 

 appeared to be entirely destitute of an apiculum even in the young- 

 est conditions that could be observed at the time. Confident that 

 two species were represented by the specimens growing at this 

 point and finding on returning to New York that the smaller plant 

 evidently had much in common with the Acetabularia Farlowii as 

 described and figured by Solms, we submitted specimens of it both 

 to Count Solms and Professor Farlow, both of whom approved 

 the reference to A. Farlowii, though with a certain amount of 

 cautious reserve in view of the scantiness of the original material. 



In March 1904, the writer again found Acetabulum Farlowii in 

 abundance, this time at Miami, Florida, and at Cutler, both on 

 Biscayne Bay. Here again, the A. Farlowii was confined to a 

 rather narrow zone near the low-water mark, while A. crenulatum 

 (which in Biscayne Bay is more profusely abundant than we have 

 yet seen it elsewhere), with a wider range, had its best develop- 

 ment in deeper water (best in 3 dm. to 4 m., low tide). The 

 zones occupied by the two species occasionally, however, over- 

 lapped ; the individuals intermingling in this common region were, 

 as a rule, easily referred at sight to the one species or the other, 

 though once in a while an individual was met with whose affinities 

 seemed at first a little dubious. Yet we believe that the two are 

 actually and always distinct and distinguishable and that the prin- 

 cipal diagnostic characters may be contrasted as follows : 



