132 PROF. W. C. WILLIAMSON CORRECTIONS OF 



the earliest known of the many types with which the labours 

 of Ehrenberg made the scientific world familiar. 



At the above period the nomenclature of these various 

 objects was in a most unsettled state; consequently the 

 specific references contained in the above memoir are very 

 defective. Some of mv fellow-labourers in this field are 

 kind enough to say that the memoir still retains sufficient 

 scientific value to make a correction of the nomenclature 

 a desirable thing. My valued friend Professor Rupert 

 Jones has not only urged me to undertake this task, but, 

 by the assistance he has kindly given me in the case of 

 the recent and fossil Foraminifera, he has made the duty a 

 light one. The following columns therefore give, on the 

 one hand, references to the figures of the various objects 

 represented in the plates to the memoir in question, and, 

 on the other, the names by which these objects are known 

 at the present day. 



Diatomacece. 



Keferences to the Memoir. Modern Nomenclature. 



Plate I. 



fig. 1. Benticella tridentata, Ehr. (p. 16) ... Biddulphia Tuomeyi. 



It is my belief that Biddulphia regina (Smith), triden- 

 tata (Ehrenberg), and Tuomeyi (Bailey) are but varieties 

 of the same species. They chiefly vary in the length of 

 their terminal processes. 



fig. 2. Biddulphia pulchella, Gray (p. 16)... Biddulphia pulchella. 



3. Amphitetras antediluviana, Ehr. ] A » . . . . j - 7 ■ 



r ' v Amphitetras antediluviana. 



(p. 16) 

 4, 6, 8. Grammatophora africana, Ehr. 



(p. 17) \ Grammatophora serpentina. 



5. , var. (p. 18) 



This not uncommon marine species varies exceedingly 

 in the form of its frustules and in the number of the 

 undulations of its characteristic vertical septa — G. angu- 

 losa, Ehr., africana, Ehr., anguina, Kutzing, mediterranean 

 Ehr., and islandica, Ehr., being but varieties of the same 



