64 COLLINS AND HERVEY. 



fig. 4; 1913, p. 127, fig. 100; Collins, 1909, p. 413; with broad, little 

 proliferous fronds. 



Forma zosterifolia Borgesen, 1907, p. 359, fig. 6; 1913, p. 127, 

 fig. 101; Collins, 1909, p. 413; with narrow, proliferous fronds; 

 Fairyland, Dec., Collins. 



5. C. CRASsiFOLiA (Ag.) J. G. Agardh, 1872, p. 13. Typical C. 

 crassifolia has not been found here; forma laxior is common, and is 

 apparently a well marked endemic form, not having been reported 

 elsewhere; forma mexicana is the common form of Florida and the 

 West Indies, and though not rare in Bermuda is less common than 

 forma laxior. 



Forma laxior (Weber) Collins, 1909, p. 413; P. B.-A., No. 1919; 

 C. pinnata forma laxior Weber, 1898, p. 291 ; C. crassifolia var. mexi- 

 cana Alg. Am. Bor. Exsicc, No. 170. Walsingham, April, Hervey; 

 Hungry Bay, Tuckertown, Gravelly Bay, Pool by Moore's calabash 

 tree. Cliff pool, April, Harrington Sound, May, Collins. 



Forma mexicana (Sond.) J. G. Agardh, 1872, p. 13; Collins, 1909, 

 p. 413; C. mexicana Sonder in Iviitzing, 1849, p. 496; Harvey, 1858, 

 p. 16, PI. XXXVII. A; Gibbet Island, Bailey's Bay, Jan., Hervey. 



The form from Cliff Pool deserves special notice; Cliff Pool is a 

 name we have used for a small but deep pool, near the SW. corner of 

 Harrington Sound, between Tucker's Bay and Green Bay. It has a 

 steep cliff on the side towards the sea; on the other side it is near the 

 Sound, but separated from it by land considerably above its level. 

 It evidently has underground connection with the Sound, the water 

 rising and falling somewhat with the tide. On the surface of this 

 pool, in April and May, 1912, was a floating mass of algae, chiefly 

 C. crassifolia, C. racemosa and C. sertularioidcs. The stolons floated 

 on the surface, the fronds extending beside them, the tapering rhi- 

 zoids hanging straight down, sometimes reaching a length of 2 dm., 

 reminding one of the roots of a Lemna or Spirodela, on a larger scale. 

 Borgesen, 1907, p. 344, classifies the Caulerpas under three t^'pes. 

 (1) The epiphytic or mud-collecting Cauperpas. (2) The sand and 

 mud Caulerpas. (3) Rock and coral-reef Caulerpas. These three 

 types are represented in Bermuda, and we can now add a fourth, the 

 floating Caulerpas. Evidently this form can occur only at a station 

 with considerable depth of water, not reached by surf, sheltered from 

 winds, and with no current. Specimens collected here in May 

 have been distributed as P. B.-A., Nos. 1873 and 2021. The station 

 was revisited in August, 1913, but only a few bleached individuals were 

 found; apparently the plants could not endure the intense heat of the 

 midsummer sun. 



