LINDSAY, ON THE PROTOPHYTA OF NEW ZEALAND, 105 
Rabenhorst (p. 108) also records it under A. coarctatum as 
British. 
101. anceps, Ehrb. 
Occurs also in Europe, Asia, Africa, and America (Smith). 
102. linearis, Ehrb. 
Occurs also in America (Smith). 
103. platystoma, Ehrb. 
Occurs also in Germany, America, and Asia: but not 
British (Pritchard). Switzerland and Southern France 
(Rabenhorst). 
104. Phenicenteron, Nitz. 
Occurs also in Sicily (throughout Europe, Rabenhorst) and 
North America (Smith). 
105. gracilis, Ehrb. 
Occurs also in North America (Smith). 
106. scaphuleformis, Grev. 
“Descriptions of New and Rare Diatoms,” ‘ Quart. Journ 
Mice. Sci.,’ July, 1866, p. 85, Pl. IX, fig. 32. 
107. rotundata, Grev. 
Ibid., p. 85, Pl. IX, figs. 30, 31. 
Genus 30. Mastogloia. 
108. lanceolata, Thw. 
Marine and littoral (Rabenhorst). 
Genus 31. Colletonema. 
109. vulgare, Thw. 
Seeats also in France (Smith): and throughout Europe 
(Rabenhorst). 
110. neglectum? Thw. 
The most interesting feature of the foregoing list is the 
very large proportion of genera and species that are British. 
Of 31 genera, only 1, or 3-22 per cent. ; while of 110 species 
only 11, or 10 per cent., are not British. The solitary 
genus in question is Hyalodiscus: while the species are 
H. subtilis, Actinoptychus undulatus, Synedra tenuis, S. acuta, 
Cymbella obtusiuscula, C. Lindsayana, Gomphonema augur, 
Stauroneis platystoma, S. scaphuleformis, S. rotundata, and 
Surirella elegans. ‘This proportion (90 per cent.) of British 
forms is much larger than what obtains in any other class 
of plants collected by me in New Zealand,* and is greater, 
* The nearest approximation occurs in the Lichens, 50 per cent. of which 
are common to Britain (“Lichens of Otago, New Zealand,” ‘ ‘Trans. Botan. 
Society of Edin.,’ vol. viii, p. 357). 
