Genus ALGITES, gen. nov. 



A generic term, for those fossils whioh in all probability belong 

 to tbe class Alga, but wbich, by reason of the absence of 

 reproductive organs, internal structure, or characters of a trust- 

 worthy nature in the determination of affinity, cannot be referred 

 with any degree of certainty to a particular recent genus or 

 family. 



1. — Algites valdensis, gen. et sp. nov. 



Type. Carbonaceous impression from Ecclesboume, near Hastings 

 (Fairlight clay). British Museum. PI. I. Fig. 1. Registered 

 number V. 2857. 



Thallus in the form of dichotomously divided branches radiating 

 from a centre ; the branches terminating bluntly. 



The apparently dichotomous habit and the shape of the thallus 

 at once suggest a resemblance to a number of algal genera, such 

 as Chondrus, Zonaria, Bictyota, Ehodymenia, Nitophyllum, and 

 others. Chondrus crispus (L.), Staokh., seems the most likely 

 species among recent forms with which to compare the "Wealden 

 impressions ; its more resistant fronds appear better adapted for 

 preservation than the more delicate structures of Ehodymenia or 

 Zonaria. So far as habit is concerned there is indeed a striking 

 resemblance between Algites valdensis and Nitophyllum Bonnemaisoni 

 (Lyngb.)^ as figured by Harvey ; but an eq^ually strong resemblance 

 may be traced on comparing the fossil specimens with examples 

 of other recent genera. The extreme variability of Chondrus 

 crispus is well known, and, as Mr. Murray pointed out to me, the 

 broader type of thallus, such as we have in Algites valdensis, is 

 indicative of quiet pools or gently flowing water, and in marked 

 contrast to the narrow filiform branches of specimens growing in 

 swiftly running currents. This difierence of habit, and its close 

 connection with the mode of life, is worth noting with reference 

 to fossil forms, although in the present instance it would hardly 

 be admissible to draw any conclusions from the breadth of the 

 thallus branches when we are in doubt as to generic relationship. 



' Harvey, pi. xxiii. fig. 2. 



