Myxoghyceae 5 ' 



diameter, spherical, usually as many as 32 developed in marginal goni- 

 dangia. 



Massachusetts. On old plants of Cladophora in upper tide pool, rocky 

 shore. Cohasset. October 1901. (Collins). Hawaii. Ditches and marshes, 

 between Honolulu and Waikiki, Oahu. 1896-97. (Schauinsland). 



Genus HYELLA Bornet and Flahault. Journ. de Bot. 162. 1888. 



Colonies radiately expanded, orbicular, composed of two kinds of fila- 

 ments; primary filaments horizontal, tangled, twisted, finally becoming 

 a very densely woven felty mass; secondary filaments vertical, developed 

 from primary; branching true; tegument septate, thicker at base of fila- 

 ment,- narrower above; cells disconnected, not joined in chains, lower ones 

 short, sometimes divided longitudinally, upper ones longer; reproduction 

 by means of vegetative cells set free from tegument and by means of 

 gonidia formed in gonidangia by successive division of contents. 

 I Colonies yellowish or olive, at first forming minute patches or dots, 

 later becoming membranaceous or cushion-shaped; erect filaments usually 

 parallel; vegetative cells usually 5-6, sometimes up to 10 mic. in diameter. 



H. cae^pitosa 



TI Colonies immersed in substance of shell, brownish-gray or bright blue; 

 vegetative cells 5-10 mic. in diameter H. fontana 



115. Hyella caespitosa Hornet and Flahault. Note sur deux nouveaux 

 Genres d'Algues perforantes. Journ. de Bot. 2: 162. 1888; Sur quel- 

 ques Plantes vivant dans le Test Calcaire des Mollusques. Bull. 

 Soc. Bot. France. 36: CLXV. pi. 10. f. 7-9; pi. 11. 1889. De 

 Toni. Syll. Algar. 5: 125. 1907. 

 Collins. Algae.— Rand and Redfield's Flora of Mount Desert Island, 

 Maine. 249. 1894. Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 

 7. no. 302. 1897. Setchell. Notes on Cyanophyceae. HI. Erythea. 7: 

 54. 1899. Collins. Preliminary lists of New England plants, — V. Marine 

 Algae. Rhodora. 2: 42. 1900; Phycological Notes of the late Isaac Hol- 

 den, — I. Rhodora. 7: 172. 1905. 



Plate III. fig. 9-II- 



Colonies at first forming minute patches or dots, later becoming mem- 

 branaceous or cushion-shaped, 1-2 mm. wide, yellowish, olive or brown- 

 ish, for a time mucous, fleshy; erect filaments usually parallel, about 10 

 mic. in diameter, 100-200' mic. long; tegument simple, gelatinous, colorless; 

 vegetative cells usually S-6, rarely up to 10 mic. in diameter, somewhat 

 globose or angular, associated in filaments, sometimes irregularly branched; 

 cell contents yellowish-olive, rarely olive to bluish-green. 



Canada. In oyster sh&lls. Malpeque, Prince Edward Island. (Faull). 

 Maine. In dead shells. Spectacle Island, Penobscot Bay. July 1894; growing 

 in the substance of dead shells. Seal Harbor. (Collins). Rhode Island. 

 (Collins). Connecticut. In shells. June, August. (Holden). Massachu- 

 setts. (Collins). California. On shells of the eastern oyster (O s t r a e a 

 virgin! an a). Probably introduced. Bay Farm Island, Alameda. (Setch- 

 ell). 



