264 SCIENCE PROGRESS. 



between the different regions, and among all three may have 

 a significance in this respect to students of distribution." 

 The writer finds that the genera of the tropical areas are 

 largely the same while the species are in a high proportion 

 different. This is particularly marked in the case of such 

 a tropical and subtropical order as the Siphonece (sensu 

 Agardh). There are twenty-three genera of this order in 

 the warm Atlantic and sixteen in the Indian Ocean, and the 

 whole of the sixteen are genera in common ; while only 

 twenty-nine species are possessed in common out of the 

 two totals of ninety-nine and seventy-two, though the 

 waters of the Cape are now warm enough to sustain such 

 generic types as Caulerpa. 



Of the other papers cited under (5) the first is a con- 

 tinuation of the study of the morphology of the Fucacece, 

 especially their conceptacles, which was initiated by Bower, 

 and carried further by Oltmanns. The generic types dealt 

 with are mostly from remote places, and perhaps the most 

 interesting is Notkeia, by Miss Mitchell, though the nature 

 of the material did not suffice for a complete study. Its 

 interest is mainly that it appears to be a much degraded, 

 truly parasitic Fucaceous genus. The second paper, by 

 Miss Whitting, describes a new endophytic Alga Chlorocystis 

 Sarcophyci, which inhabits the fronds of Sarcopkycus, and 

 appears to be most nearly related to the interesting form 

 described some years ago by Dr. Perceval Wright, as 

 Chlorochytrium Cokn'u occurring in various Algae in our 

 own seas. The next paper by the present writer is a 

 study of Halicystis (a genus new to Britain) and Valonia, 

 of which latter genus the mode of reproduction is described. 

 In her paper on Hydroclathrus Miss Mitchell describes the 

 vegetative and reproductive structure of a singular type, and 

 in the following paper the present writer gives an account 

 of his examination of the cryptostomata (fasergriibchen) of 

 three genera of Laminariacece and compares their develop- 

 ment, etc., with those of the Fticacece and Splachnidiacece, 

 and ventures certain speculative views as to the significance 

 of these puzzling structures. 



Dr. Schiitt gives (6) a valuable account of the results 



