2 ALG^J. 



of the misuse of one of the names, Caulerpites, the remarks of 

 Murray on fossil Caulerpas are worthy of repetition. In his recent 

 paper on an example of this genus from the Kimeridge clay he 

 says 1 "I have examined nearly every species known to science 



of those (Caulerpa sp.) at present existing of all the 



described fossil Caulerpce or Caulerpites of which I have seen 

 specimens and figures, there is not one which might not with 

 equal propriety be assigned a place elsewhere within or without 

 the vegetable kingdom." In looking at the specimens of Murray's 

 new species, Caulerpa Carruthersii, one easily recognises the 

 resemblance to the recent genus, and it is difficult to imagine to 

 what other source such impressions could be referred. It is 

 somewhat surprising, however, to find what deep and well-defined 

 depressions have been left in the rock by this Oolitic seaweed. 



It is superfluous to point out what very little value we can attach 

 to external form in many of the carbonaceous impressions on rock 

 surfaces ; the same general habit of thallus being found in several 

 recent genera, and indeed in different families. Unless, therefore, 

 we are dealing with examples where the fossil clearly shows 

 a habit strikingly similar in form to that of a well-marked and 

 distinct recent genus, or with specimens exhibiting a well-preserved 

 internal structure, or clear indications of characteristic reproductive 

 organs, by making use of recent generic names we are rather 

 hindering than advancing the knowledge of fossil phycology. Eor 

 these reasons it is safer to be content with merely pointing out 

 such living genera as approach most nearly in habit the algal- 

 like impressions, and not commit ourselves to a doubtful and 

 misleading affinity by referring the fossil forms to particular genera 

 or families. 



"With a view to having some general term which may serve as a 

 provisional generic name for fossils, which in all probability come 

 under the head of Algce, but which it is impossible with any 

 degree of certainty to refer to a definite recent type, I propose 

 to use the word Alyites. 



Schlotheim, 2 and also Sternberg in his earlier writings, adopts 

 the term Algacites as a comprehensive title for all fossil seaweeds. 

 In the later parts of the "Flora der Vorwelt " those " algal " 



1 Phycol. Mem. pt. i. 1892, p. 13. 

 8 Petrefactenkunde, p. 38. 



