438 NEW OR CKITICAL BHITISH MARINE ALGM. 



tufts, usually more or less widely separated from each other. Cells 

 from 9-60 [x in length. Tetraspores terminal or lateral, in the 

 latter case borne on short stalks, large in proportion to the size of 

 the plant, solitary or clustered, oval or oblong, from 18-30 {x long, 

 and from 20-80 /x broad. Hab. : Rennie Eocks, Plymouth, June, 

 1896, (ho. Brchner. 



This very interesting species gives little outward indication of 

 its presence. It does not appear to injure the host-plant in any way, 

 as the specimens of Glceosiphonia, in the fronds of which it was 

 found, were perfectly healthy, and bore antheridia and cystocarps 

 in abundance. The habit of the plant bears a striking resemblance 

 to that of a Strehlonema. The tetraspores are very large and con- 

 spicuous, and clearly cruciately divided. I have dedicated the species 

 to its discoverer, Mr. Geo. Brebner, who has done excellent service 

 to British algology. 



15. Harveyella pachydekma (Choreocolax pachydermus Reinsch, 

 Contrib. ad Algol, et Fungol. tab. 50). In the recently issued fasci- 

 culus of his AlgcB exsiccatce, Mr. Holmes has distributed specimens 

 of a Hari-eijeUa collected at Gosport in December of last year by 

 Mr. H. N. Sturch. These specimens were supposed, both by Mr. 

 Holmes and myself, to belong to Kuckuck's Choreocolax albus, 

 which, however, turns out to be only the tetrasporic form of 

 Harveyella mirahilis. Mr. Starch's specimens, which bear both 

 cystocarps and tetraspores, appear to be referable to Reinsch's 

 Choreocolax pachyderimis, which was also found parasitic on the 

 fronds of Gracilana confervoides, rather than to his C. mirahilis. 



16. CoRALLiNA viRGATA Zan. Sagcj. di Class. Nat. d. Ficee, p. 42. 

 Bangor, Ireland. Mrs. Barwell Carter, a daughter of the late Dr. 

 Geo. Johnston, of Berwick-on-Tweed, recently very kindly presented 

 me with a small collection of "British Lithophytes " which had 

 beloiiged to her father ; amongst them were two specimens of the 

 present species from "Bangor, Ireland," marked in Dr. Johnston's 

 writing " Corallina officinalis, var." 



17. Melobesia biyriocaepa Crouan, Flor. du Finist. p. 150. 

 Plymouth, Fj. a. B. ; Weymouth, E. M. Holmes. Specimens of 

 this species have been distributed by Mr. Holmes in his Alga 

 exsiccatcB. 1 first detected this species on pieces of glass, &c., 

 dredged from 5 to 8 fathom water in Plymouth Sound. My speci- 

 mens agree well with Crouan's description, as do those distributed 

 by Mr. Holmes, but it is quite possible that the plant may have 

 previously been described under some other name, as it is almost im- 

 possible to recognize some of Kutzing's species from his descriptions. 



18. Hildenbrandtia Crouani J. Ag. Spec. Alg. vol. ii. p. 495. 

 {Hildcnbrandtia rosea Crouan, Fl. Finist. p. 148, tab. 19, gen. 126.) 

 Teignmouth, T. H. Bufiham; Berwick, E. A. B. Prof. J. G. 

 Agardh divides the genus Hildenbrandtia into three sections or sub- 

 genera, the first — Hildenbrandtia proper — is characterized by the 

 irregularly divided tetraspores, which vary in form from regularly 

 cruciate to regularly zonate ; the second sub-genus — Hceniatophloea — 

 is characterized by the regularly zonate tetraspores ; the third 



