420 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



base to the summit, or, where there is a distinct pedicel, the 

 passage from the pedicel to the summit is not sudden. 



One of the most variable of Caulerpas, covering many former 

 species, now arranged under varieties and forms that give no 

 sharp division lines ; occurring in one form or another all over 

 the world, mostly in shallow water. Of the 8 varieties given 

 by Mme. Weber, 5 occur with us, also another variety of Borge- 

 sen ; the following key may be some guide to them. 



i. Ramuli usually pyriform-obovoid, with globular or subglobular sum- 

 mit, occasionally laterally flattened ; pedicel not over half the 

 total length of the ramulus. . 2. 



i. Ramuli claviform with rounded or trumpet-shaped summit ; some- 

 times also cylindrical ramuli present ; pedicel often more than 

 half the total length of the ramulus. 3. 



2. Fronds with distant, alternate or distichous and subopposite ram- 

 uli, usually pyriform with globular summit. Var. clavifcra. 

 2. Fronds with multiseriate, imbricate, obovoid or obovoid-compressed 



ramuli. Var. uvifera. 



3. Slender and delicate plauts. Var. gracilis. 



3. Stout. 4. 



4. Ramuli multiseriate, densely imbricate. 5. 



4. Ramuli few or wanting. Var. Lainonroii.vii. 



5. Ramuli rather uniformly increasing in size to summit. 



Var. laetevirens. 

 5. Ramuli suddenly expanded at summit. Var. occidentalis. 



Var. CLAVIFERA (Turn.) Weber, 1898, p. 361 ; Vickers, 

 1908, p. 28, PI. XLV. Slender, i-n cm. high, ramuli gener- 

 ally distant, usually pyriform with globular summit, 1-2.5 mm - 

 diam., and short pedicel. Fla., W. I. All tropical seas. 



Forma MACROPHYSA (Kiitz.) Weber, 1898, p. 361 ; P. B.-A., 

 No. 870. Ramuli with globular summit 4-5 mm. diam. Jam- 

 aica, St. Croix. 



Var. UVIFERA (Turn.) J. G. Agardh, 1872, p. 35. Frond 

 .cylindrical, simple or branched, with very dense, multiseriate 

 ramuli ; ramuli usually obovoid, sometimes globular. Red Sea. 



Forma CONDENSATA (Kiitz.) Weber, 1898, p. 363. Ramuli 

 very dense at the base of the frond, more open .near the top. 

 W. I. (forma condensata only). 



Var. OCCIDENTALIS (J. Ag.) Borgesen, 1907, p. 379, figs. 28 

 and 29. Ramuli subcylindrical and rather loosely set at the 

 base of the rachis, more clavate and closer above, densely im- 

 bricate at the summit ; top of ramuli always convex. W. I. 



Var. LAETEVIRENS (Mont.) Weber, 1898, p. 366. Fronds 



