SPORANGIA OF ECTOCARPUS BREVIARTICULATUS 51 



but mature galls were at my disposal. In one case the cystocarp 

 had been attacked, but in another specimen the galls arose from 

 the vegetative part of the thallus, as in Furcellaria. If sections 

 across thallus and gall are stained with anilme blue, the colour is 

 only taken up deeply by the uninjured parts of the thallus, and the 

 diseased portions containing the colonies of nematodes remain much 

 lighter in colour. 



Finally, I offer my best thanks to Mr. V. H. Blackman, to whom 

 I owe the observations on the starch-like granules. 



SPORANGIA OF ECTOCARPUS BREVIARTICULATUS. 



By Ethel S. Barton. 



(Plate 418, figs. 7, 8.) 



During an investigation of some material of Chnoospora atlantica 

 J. Ag., collected at St. Vnicent, West Indies, by Mr. W. R. Elliott, 

 I was led to examine the tufts of Ectocarpus breviarticulatiis 

 growing on it. This proved to be in fruit, and, as the sporangia 

 have never been described for this species, it may be of interest 

 to do so now. 



The sporangia in question are plurilocular, and occur sparingly; 

 they are of an ovate form, with the upper end more or less pointed, 

 and vary from 20-35 /x in breadth and 60-90 /a in length. They 

 arise generally from a short pedicel cell, but occur also sessile, 

 and even sometimes as the termination of a short two-celled 

 branch. 



In Prof. Agardh's original description of E. breciarticalatm 

 (Nya alger fian Mexico, Kongl. Vet.-Akad. 1847, p. 7), the cells of 

 the primary creeping filaments are said to be shorter than their 

 diameter, while the cells of the secondary filaments are 1^ times as 

 long as their breadth. Tliis, however, is not a constant charac- 

 teristic in the St. Vincent material : in some cases longer cells 

 appear in the primary filament, and very often short cells are 

 found in the superior filaments. Some of the latter are figured here. 



Explanation of Plate 418. — Fig. 1. Furcellaria fastujiata Lam. with 

 galls, nat. size. 2. Ditto, thallus, showing early stage of gall, x 260. 3. Ditto, 

 later stage of gall, x 130. 4. Ditto, mature galls, x 25. 5. Chondrus ciisiJus 

 Stackh. with galls, nat. size. 6. Ditto, transverse section of mature galls and 

 thallus, x 6. 7. Ectocarims hreviartkulatm J. Ag., plurilocular sporangium, 

 X 375. 8. Ditto, some cells in an upper filament. 



E 2 



