ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 619 



different, and the author in the present paper describes both in detail. 

 In anatomical characters H. lorea shows, of course, marked agreement 

 with other families of the Fucaceas, but it also recalls in some points 

 the anatomy of the Laminariaceae. Since the latter similarity is not to 

 be explained by genetic relationship, it is probably caused by external 

 conditions of life, and the more so since the habitat of Himanthalia and 

 Laminaria is in general the same. The investigations here described 

 were carried out on living material only, an essential condition in a study 

 of either Fucaceaa or Laniinariaceas. 



Compsopogon.* - - H. Murray records having found a quantity of 

 Gompsopogon leptocladus in the Reddish Canal, in Lancashire. Its dis- 

 tribution is purely tropical and sub-tropical, and it has never till now 

 been recorded for Europe. Other aliens are also recorded for the 

 Reddish Canal, but no explanation is given for their presence in Lanca- 

 shire. 



New Parasite on Gracilaria confervoides.f -- H. L. Wilson has 

 carefully examined certain tubercles or granules which are scattered pro- 

 fusely over the thallus of Gracilaria ronfervoides in San Francisco bay. 

 They are colourless, and resemble sand grains or small particles of rice, 

 being, in fact, from 1-2 mm. in any diameter. They are normally 

 spherical in shape and smooth, and from their white colour are con- 

 spicuous against the dark thallus of the Gracilaria. Superficially the 

 tubercles are alike, but in reality they are of three different kinds, each 

 kind being devoted to the development of its particular organ of repro- 

 duction, tetrasporangia, autheridia, or cystocarps. There is no signifi- 

 cance in the place they occupy on the Gracilaria, nor does their size offer 

 any aid in determining their identity, for the smallest as well as the 

 medium and the largest show well-developed organs of reproduction. 

 The structure of each sort of tubercle is minutely described, and the fol- 

 lowing summary is given. The tubercle differs in tissue and structure 

 from the Gracilaria on which it is found. It is provided with its own 

 independent means of reproduction. It is furnished with numerous fila- 

 mentous processes or rhizoids, that serve as a means of nourishment ; 

 and being thus amply endowed for the exigencies of its own existence, it 

 must be classed as an independent plant. This plant, showing entire 

 absence of colour, and provided with ample means of drawing its nourish- 

 ment from another plant, must be classed with the parasites. Though 

 this parasite is closely related to its host-plant, it cannot, on account of 

 certain differences, be placed in the same genus ; and therefore the author 

 proposes the name of Gracilariophila for it, and calls it G. oryzoides. It 

 has also been recorded on Gracilaria multipartita, and is found on the 

 coasts of California. 



Lithothamnium calcareum.t. — P. Lemoine has made a study of 

 this alga, and writes fully on its distribution and manner of life. It is 

 extensively used on the coasts of Brittany for liming and improving the 

 soil. The species is extremely variable in habit, and many forms of it 



* Lancashire Nat., ii. (1909) p. 72. 



t Univ. California Publications (Bot.) iv. (1910) pp. 75-84 (2 pis.). 



j Annales de l'Institut Oceanographique, i. fasc. 3 (1910) 30 pp. (1 pi.)- 



2 T 2 



