PROTOCOCCACEAE. 597 



5. DILOPHUS J. Ag. Till Alg. Syst. 2: 106. 18S2. 



Segments mostly 0.3-1 mm. l)ro:ul, the apices ncute. jicuminate or subobtuso • raodulla 

 2-4 cells thick or here and there only 1 cell thick. 1. D.ijuintnisia 



Segments mostly 1-L' mm. broad, the apices ol)tusp : medulla 2-.j 



cells thick at or near the margins, 1 or 2 cells thick in the middle. 2. It. altirnaitH. 



1. Dilophus guineensis (Kiitz.) J. Ag. loc. cit. 108. 



Spatoglossum guincense Kiitz. Phyc. Gen. 339. 1S43. 

 IDictyota Antiguae Kiitz. Tab. Phyc. 9: 16. pL 37. f. II. 1859. 

 Dictyota guineensis Crouan; Maze & Schramm, Alg. Guad. 126. 1870-1877. 



On rocks in shallow water in rather exposed situations. Rose Island, Berry 

 Islands, Great Bahama. Gun Cay, Watling's Island. Mariguana. Caicos Islands. Little 

 Inagua. and Great Ragged Island : — Bermuda and Florida to Jamaica and Barbados. 

 Type from St. Thomas. 



Often proliferous along the middle line and often closely resembling Dictyota 

 cervicornis but usually darker on drying. 



2. Dilophus altemans J. Ag. loc. cit. 108. 



On rocks near low-water mark. Gun Cay. North Cat Cay. South Cat Cay, and 

 Caicos Islands: — Florida to Barbados. Type* from Key West,' Florida. 



6. DICTYERPA Collins, Proc. Am. Acad. Arts an-l Sci. 37: 251. 1901. 

 1. Dictyerpa jamaicensis Collins, loc. cit. 



On rocks in shallow water. South Cat Cay and Watling's Island : — Jamaica. 

 Type from Jamaica. 



Resembles narrow conditions of Dilophus f/uincensis, but is more irregular in its 

 branching and is terete or subterete, with a medulla more than four cells wide. 

 Phyc. Bor.-Am. 780 in herb. N. Y. Bot. Gard. shows tetrasporangia (?) similar to 

 those of Diloi)hus i/»//!Cf?isi'.s. 



Sub-class CHLOROPHYCEAE. 



Family 1. PLEUROCOCCACEAE. 



1. PSEUDOTETRASPORA Wille, K. Xorske Vi.lensk. Selsk. Skr. 

 1906=': 20. 1906. 

 1. Pseudotetraspora Antillarum M. A. Howe, sp. nov. 



Thallus subglobose, obovoicl, pyriform, saccate, or allantoiil, variously 

 wrinkled, constricted, or bullate, mostly 2-20 mm. in length or height, often 

 more or less explanate and laeunose with age, yellowish brown when living, 

 brownish or dark brown on drying; cells subglobose or ellipsoid, mostly 3-7 m 

 in maximum diameter. 



Enveloping leaves of Halodulc and Thnlassia and older parts of the thallns of 

 Chondria Uttoralis and other marine algae, in shallow water. Sometimes washed 

 ashore in great quantities. New I'rovidenco. Roso Island, K.\uma Chain and Cat 

 Island. Type Hoirc S!,.',S, Rose Island. Jan. 2S. lOo.". 



The species apparently differs from the Norwegian /'. mnrina WiUe in Its yel- 

 lowish brown color, its larger more saccate or allautoid thallus. and the somewhat 

 smaller cells. 



Family 2. PROTOCOCCACEAE. 



1. PROTOCOCCUS Ag. Syst. Alg. 13. 1S24. 



1. Protococcus viridis Ag. loc. cit. 



Flcuroeoccus vulgaris Naeg. Gatt. einzel. Alg. 65. pi. iK. f. :2. 1S49. 



On trunks of trees, etc. (det. F. S. Collins), pr(>l)al>ly common. New Provi- 

 dence : — cosmopolitan. Type from Sweden. 



