and on the east from the British Islands to the Cape of 

 Good Hope. It is also found on the shores of the 

 Mediterranean and Adriatic. Harvey [Ner. Bor. Amer., 

 III., p. 29, and Phijc. Brit., vol. IV.), however, considers 

 it to have a much wider range, by including under the 

 species forms which are by other authors, and amongst 

 these Agardh, ranked as distinct species. If we accept 

 Harvey's view, then its distribution would be " all the 

 shores of Europe, both Mediterranean and Atlantic. 

 Dispersed also throughout the temperate and torrid por- 

 tions of the Atlantic, Pacific, and Indian Oceans. New 

 Holland and Tasmania. Auckland Islands." 



Locally, so far as we have been able to find out, Coclium 

 tomentoswm has been recorded from one situation only, 

 namely, the south end of the Isle of Man. It occurs in 

 shallow rock pools at or near low water mark, at Port 

 Erin and at Fleswick Bay. From these regions our 

 material was obtained fresh, and kept growing in salt- 

 water tanks in the Laboratory. The plants are per- 

 ennials, and fruit freely (at all events, in these localities) 

 in winter. The time for fruiting is generally given as 

 November. Plants sent to us in February had abundant 

 fruit. We have not as yet had the opportunity of exam- 

 ining material collected at any other period of the year. 

 Most of the sporangia had shed their contents by March. 



General Morphology. 



Plants of Codium tomentosum most commonly grow in 

 more or less dense clusters, arising from a basal expansion 

 which is intnnately connected with and attached to the 

 substratum, rock, sand, or broken shell debris (PI. I., fig. 

 1). The erect shoots are branched and cylindrical. The 

 branching is usually dichotomous but occasionally mono- 

 podial. The branches vary in thickness, bat in a well 



