47 



folia, and Caulerpa Vickersii. Described earlier also and here 

 maintained are the genera Cladophoropsis and Ernodesmis, with 

 Conferva memhranacea Ag. and Valonia verticillata Kiitz. as 

 types, respectively. Several species, originally described from 

 other parts of the world are attributed to the West Indies for 

 the first time by Borgesen, among them Boodlea siamensis and 

 Acetabularia Caly cuius, the latter having been first known from 

 the Australian region. 



Borgesen makes a rather free use of varietal and form names, 

 as is seen especially in his treatment of the Halimeda tridens 

 group (for which he prefers the name Halimeda incrassata). 

 Halimeda Monile and H. simulans are considered to be varieties 

 of H. incrassata. The present reviewer has seen and handled 

 thousands of plants of this group on the shores of Bermuda, 

 Florida, the Bahamas, Cuba, Porto Rico, Jamaica, and the 

 Isthmus of Panama, and as elsewhere explained* feels convinced 

 that (excluding H. favulosa) they represent three absolutely 

 distinct species. They often grow very closely associated, under 

 apparently identical conditions, yet maintain their distinctive 

 characters perfectly. In ninety-nine cases out of a hundred, 

 they may be distinguished at first sight, and in occasionally 

 occurring individuals the position of which may seem at first 

 sight doubtful, a comparison of the size of the peripheral utricles 

 is, we believe, always sufficient for the determination. Borgesen 

 claims to have found cases in which large and small utricles may 

 occur on different parts of a single plant, which may very natur- 

 ally happen, but if he would use in such cases the general average 

 of sizes in making his comparisons we believe his difficulties 

 would vanish. In similar fashion the reviewer has often seen 

 Caulerpa racemosa and Caulerpa clavifera growing in close 

 proximity, under apparently identical conditions, and is inclined 

 to accept the view of Svedelius that the supposed intergrading 

 of these two forms is apparent rather than real and that their 

 true relationships are best expressed by referring them to the 

 specific category as was done by the earlier writers. Unfor- 

 tunately, in this genus, there seems to be nothing but external 

 form that one may lay hold of in attempting to limit species. 



* Bull. Torrey Club 34: 501-504. 1907. 



