i8 9 6. RECENT WORK ON SEAWEEDS. 37 



expected, very similar to those at the Cape, though the two places 

 are in such different latitudes. On the west coast, however, we find 

 a different state of affairs. There is a cold current which comes up 

 from the south, bringing icebergs as far north as 35 50', and this 

 has naturally a marked effect on the algse all up this coast." 



Another paper, dealing exclusively with distribution, by Mr. Murray 

 and Miss Barton (11), in the last number of the recently-completed 

 volume of the Phycological Memoirs compares the Arctic and Antarctic 

 marine floras. There are fifty-four species common to the north and 

 south of the tropical belt, but not occurring within it, a fact that points 

 to a uniform temperature of the sea from equator to poles in early 

 geological ages. The authors quote from Dr. John Murray's " Sum- 

 mary of the Results of the ' Challenger ' Expedition," the theory first 

 introduced into geological speculation by Blandet (Bull. Soc. Geol. de 

 France, ser. 2, vol. xxv., p. 777 ; 1867-68), that the size of the sun was 

 much greater in the early stages of the earth's history. The sun was 

 so great, relatively to the earth, that at the equinox its rays fell on the 

 planet from pole to pole, and some degrees beyond, giving a day of 

 twenty-four hours at each pole simultaneously. There would thus be a 

 high temperature and sufficient light to permit of the " luxuriant 

 vegetation that once flourished in these regions." Explain the facts 

 as we may, it is very remarkable to find so many species common to 

 two areas so entirely separated from each other. Another fact, dis- 

 closed by the distribution-tables, is the change from the northern 

 Fucaceae to the Sargasseae of the tropical belt, and then to other 

 Fucaceae in the southern seas, "these last resembling the northern 

 forms in general facies, but yet generically distinct in most cases." 



In the department of morphology there have been several 

 interesting contributions, notably those by C. Sauvageau on Ecto- 

 cavpus (12, 15); it is just such observations and careful records that are 

 necessary to complete our knowledge of even such common Algae 

 as those he describes. Ectocavpus tomentosus, he finds, has many- 

 chambered sporangia with zoospores, which, after swarming, come to 

 rest and germinate without conjugation. It bears also single- 

 chambered sporangia, which contain motionless spores, a condition of 

 affairs which is as yet recorded for no other species. Ectocavpus pusillus, 

 an equally aberrant species, has immobile spores in many-chambered 

 sporangia. Mr. Sauvageau gives an account of four varieties of E. 

 pusillus (15), viz., vars. typica and ripavia, which are epiphytic on 

 Covallina officinalis and Polysiphonia, and vars. Codii and Thuretii, which 

 are endophytic, the one in Codium, the other in Ncmalion and Helmin- 

 thocladia. Though differing in habitat and general facies, they corre- 

 spond in the size of the filaments and in the many-chambered 

 sporangia with the large immobile spores, as also in the presence of 

 " short flexuous fibres," noted by Mrs. Griffiths as so distinctive of 

 E. pusillus, which, tendril-like, hold the filaments together, or serve to 

 attach the parasite to the host-plant. Kjellman's classification of the 



