112 Dr. G. Dickie on the Marine Alga 



Harvey's t Manual ' as occurring in Britain are found here; the 

 proportions will be best seen from the following tabular view. 



Aberdeen. Britain. 



Fucoideae 7 16 



Lichineae 1 2 



Laminarieae 3 7 



Sporocbnoideas 2 7 



Dictyoteae 6 18 



Ectocarpeae 12 25 



Chordarieae 3 5 



Total number of species 34 80 



Among the Fucoidece the total absence of Cystoseira will be 

 observed, and scarcely one-half of the British species occur ; of 

 LaminariecB scarcely one-half ; of Sporochnoidece only one-third, 

 the two species of Desmarestia being generally distributed in 

 Britain. There is also a great deficiency in the Dictyoteae, Cut- 

 leria, Halyseris, Padina, Dictyota and Striaria being totally 

 absent. Of Ectocarpece about one-half of the British species are 

 found, and three out of five Chordariece. 



It is proposed at an early opportunity to communicate observa- 

 tions similar to the present on the Rhodospermece of this coast. 



The results obtained from careful dissections of the fructifica- 

 tion of our Melanospermece have led to similar examinations of 

 species from other parts of Britain, of which I possess and have 

 only seen dried specimens. These may now be recorded, allow- 

 ance being necessary for the disadvantageous circumstances un- 

 der which the dissections have been made. 



Dichloria viridis, Grev. — On this plant Dr. Greville states that 

 he has seen no pencils of filaments. On a dried specimen received 

 through the liberality of Mrs. Griffiths they certainly are present ; 

 it also appears to have nearly the same structure as Desmarestia, 

 and not such as is represented in the ' Algse Britannicse' ; drying 

 and pressure have, however, probably produced some change. If 

 pencils of filaments (miniature fronds ?) are usually produced by 

 it, the remarks already made in reference to Desmarestia will also 

 be applicable here. 



Sporochnus pedunculatus, Ag. — Described in Harvey's ' Ma- 

 nual' thus : " Fructification club-shaped moniliform filaments, 

 radiating in scattered warts or concentrical in distinct (mostly 

 clavate, stalked) receptacles, often terminated by a deciduous 

 tuft of filaments." The clavate receptacles consist of a central 

 tissue continuous with the short stem, and a cortical, composed 

 of branched filaments placed perpendicularly to the former, and 

 concrete. The pencils of filaments consist of the free ends of the 

 central fibrous tissue. The cortical part (branched filaments) 

 contains distinct asci and sporidia ; these were very evident in a 



