of the vicinity of Aberdeen. 7 



coast being for the most part sandy ; tlie rocky part commencing 

 only on the north side of the estuary of the Yethan, a distance of 

 about sixteen miles from Aberdeen. 



The part of the Kincardineshire coast which has been examined 

 is chiefly composed of granite and gneiss ; it is much exposed to 

 the action of heavy seas, and presents few sheltered coves or even 

 calm pools of any extent, and hence probably we may account for 

 the absence of some of the more delicate species. I regret that 

 my records of the temperature of the sea at this place are so few 

 and little trustworthy as to be undeserving of record. 



The arrangement given in Harvey^s ' Manual of the British 

 Algae ^ will be followed, although his divisions, founded on the co> 

 lour of the seeds, are not strictly applicable in all cases. 



Melanosperme^. 



Halidrys siliquosa, Lyngb. — Both varieties of this plant occur 

 in considerable quantity ; it is invariably found in pools, mostly 

 at high-water mark, and is generally, or more probably always 

 submersed. 



Before proceeding to notice the species of Fucus occurring 

 here, it will be requisite to direct attention to the fructification of 

 this genus, more especially in reference to Dr. Montagne^s paper 

 in the ^ Annales des Sciences Naturelles,^ October 1842 ; in which 

 work that profound cryptogamist has published observations on 

 his new genus Xiphophora, and in connexion with it has discussed 

 at considerable length the question, whether the Fucacece may not 

 have two modes of propagation ? 



In Harvey^s work the fructification of the Fucoidece is defined 

 as " consisting of spherical clusters of opake seeds, imbedded in 

 distinct gelatinous receptacles, and finally escaping by pores -,'' 

 of Fucus more particularly it is said, that '^ the receptacles con- 

 tain tubercles imbedded in mucus, and discharging their seeds 

 by conspicuous pores.^^ 



On dissecting these so-called tubercles in difi'erent stages, more 

 especially in the earlier, it will be found that they are in reality 

 small sacs, or inflexions of the surface of the frond, having distinct 

 walls composed of condensed cellular tissue and each opening by 

 a small orifice, and having a close resemblance to the perithecia 

 of a Spharia, or the so-called anthers of Marchantia. From 

 the walls of the sacs originate numerous jointed filaments, in 

 some cases simple, in others branched ; the apices of many of 

 these protrude from the orifices of the sacs, and present no great 

 obstacle to the emission of the seeds, but prevent the entrance 

 of any small body from without. Dr. Montague's account of the 

 structure of Xiphophora corresponds exactly with this : the sacs 

 he calls conceptacles, and compares the filaments to paraphyses. 



