1'ALMELLACE.E. 



15 



Palmodictyon viride. Kutz. Tab.Phy. I. t. 31, /. 1. 



Thallus mucous, irregularly reticulate, about the thickness 

 of a hair, greenish ; cells biserial, with a very thick homoge- 

 nous tegument. 



SIZE. Cells without tegument, -0075--009 mm., with the 

 tegument '025-'04 mm. (Rabh.). 



Ilabh. Alg. iii. 37. Kutz. Phy. Germ. p. 155. 



In ditches, canals, &c., attached to stones, twigs, &c. 



Eecently found by Mr. E. Parfitt near Exeter, of which he gives the 

 following account : " The plant, where it has sufficient room to develope 

 itself, spreads over the bottom, in water about six inches deep ; beyond 

 this it comes in contact with Elodes canadensis, over which it creeps, and 

 extends its growth from branch to branch into deeper water. In this 

 extension it has first the appearance of a Conferva, which I at first took 

 it to be ; but the moment I touched it, after taking some from the 

 water, I found from the soft slimy feel that if a Conferva it was new to 

 me, and the mici'oscope soon revealed the true character. When the 

 plant grows on the bottom it shows one continuous green membrane, 

 stretched tight over the bottom, but when it comes in contact with other 

 plants it throws out filaments, the thickness of which is difficult to make 

 out on account of their adhesive nature ; for wherever they touch it is 

 matter of impossibility to separate them. The membrane forming the 

 filaments is structureless, but the sphserical cells, which form more or 

 less moniliform threads, sometimes running in parallel lines, at other 

 times forming an irregular net-work on the inside of the filaments. 

 These cells sometimes divide into two portions, at others into four, and 

 in most of the mature cells may be observed four cellules." Grevillea, 

 iii., p. 29. 



Plate VIII. Jiff. 2. a, portion magnified 200 diam. ; 6, fragment 



magnified 400 diam. 



Palmodictyon rufescens. Kutz Spec. 234. 



Is usually referred here on the faith of the remark by Kutzing, that it 

 was found at Aberdeen by Dr. Dickie. Upon enquiry of Dr. Dickie we 

 learn that he knows nothing of the species. He says, " Palmodictyon 

 rujescens is unknown to me, many years have passed since I corres- 

 ponded with Lenormand, and I do not remember receiving any note 

 from him regarding it. Kutzing (Spec. 234) is responsible for the name. 

 I cannot find in my collection anything so named, neither do I re- 

 member where the so-called material was collected." Under these cir- 

 cumstances it is useless repeating the name in connection with British 

 Algae. 



GENUS 10. TETRASPORA. Link. (1810) 



Thallus gelatinous, membranous, or submembranous, in the 

 beginning a short sac, afterward expanded ; cells globose or 

 angular, more or less distant, but associated in a single stratum 

 into large families. Tegument thick, very rapidly diffluent into 

 a homogenous mucous. Division in two directions in the same 

 plane. 



