BHODOXBULC&K. JO 



of this plant Beems to be mud-banks or mud-covered rocks. 

 It requires some algological zeal to hunt over such ground, 

 which, to many collectors, would appear little likely to yield 

 anything bo beautiful ; yel such ground is very favourable 

 to the growth of many of this genus, and of the finest Col* 

 lithamnia. At Venice it is the commonest of the genus; 

 but Venetian specimens are greatly inferior in Bize and 

 beauty to some of their Plymouth brethren. Those which 

 I have received from Dr. Bailey of New York are nearest 



to the luxuriance of the latter. 



120. obscura [Th<- dusty Polysiphonia)} densely matted to- 

 gether, filaments creeping, throwing up erect, Bimple, Becund 

 brandies, which ;uv either naked or furnished with a few Be- 

 ound ramuli; articulations as Long a- broad, many-tubed, 

 J. A<j. Alg. Medit. p. 123. (Atlas. PL XXV. Fig. 111.) 



Hutchinsia obscura, Ag. Conferva Intertexta, Both. 

 llah. Jersey and Sidmouth. Spreading over marine rocks, at half- 

 tide level; also parasitical on Fed, and on some of the smaller 

 Alga?. 

 I had at first confounded tl lis plant with I\ secunda, 

 Mont., a plant to which, outwardly, it hears a strong resem- 

 blance, hut from which it differs in length, and composition 

 of the articulations. 1 have now minutely compared the 

 British specimens with one of P. obscura received from 

 Prof. J. Agardh, and find them to agree in all essential 

 particulars ; ours are. however, rather more robust than the 

 Adriatic plant, and the joints slightly shorter. 



121. simulans | The deceptive Polysiphonia); filaments .-lender, 

 bushy, branched from the base; branches alternate, patent, 

 repeatedly (hut irregularly) pinnate j the penultimate branches 

 lon^ and Bimple, Bel with Bhort, distant, Bpine-like ramuli; 

 articulations of the branches once and half as long as broad, 

 of the ramuli Bhorter, many-tubed ; Biphons about twelve; 

 ceramidia globose or ovate, Han. Man.ed. ^.y/.s'j. (Atlas, 

 PL XXVIII. Fig. L26.) 



Polysiphonia Bpinulosa, Qriff. V. divergens, var., Ktz. 



Hah. Jersey, Torquay , Orkney. On rocks, etc., in tide-pools near 



low-watermark. Annual? Summer. Rare. 



By comparing the figure of this species with thai ^\' P. 

 subultfera, it will he seen that there is a very near rela- 

 tionship between them, and. except for some ditl'erei. 



habit and minor differences in structure, the two might 

 perhaps he brought together, Prof. J. Agardh, however, 



