Dr. WalHcli on the Tthizopods. 329 



Carter, Hertwig, Greef, and others. Indeed, as he himself 

 admits, " his attention has been more particularly directed 

 to the discovery and determination of the various forms of 

 Rhizopods occurring in North America, rather than to the 

 elaboration of details of structure, habits, modes of develop- 

 ment, and other matters pertaining to their history, though 

 these have not been entirely neglected " [op. cit. p. 2). 



The only portion of the volume that appears to me to fall 

 short of the general standard of technical excellence is the 

 purely bibliographical index, which is here and there ren- 

 dered almost unintelligible throtigh an undue multiplication of 

 synonyms and the clerical errors which have occasionally crept 

 into it. But its very compendiousness, which of itself must 

 have involved a vast amount of labour, may well be allowed 

 to turn the balance against any shortcomings of the kind 

 referred to. 



I sincerely wish certain errors in the work, of another 

 kind, could be as easily passed by without further comment. 

 Unfortunately, for reasons which will develop themselves as 

 I proceed, they cannot be so. But when they are pointed 

 out, I venture to think that, from whatever cause they may 

 have arisen, Prof. Leidy himself will be the first to acknow- 

 ledge them, quite as much in his own interests as in mine. 



Nothing, therefore, of minor import to me personally than 

 the facts about to be noticed could have induced me to criti- 

 cise certain statements made by Prof. Leidy in reference to 

 my published opinions concerning the freshwater Rhizopods, 

 in a manner which, although unavoidably adverse, will, I 

 trust, never appear hostile ; more particularly as the United 

 States Survey Department have done me the great honour 

 of presenting me with a copy of his magnificent volume. 



At page 7 Prof. Leidy makes the following remark : — " Dr. 

 Wallich (Annals & Mag. Nat. Hist. 1863, xi. p. 438) divides 

 the Rhizopods into three orders, the Herpnemata, Protodermata, 

 and Proteina. In the first are included the Gromidai, Fora- 

 minifera, and Polycystina ; in the second the Thalassicollina 

 and Acanthometrina ; and in the third, the Actinophryna, 

 Lagynida, and Amoebida." 



As already stated, within a couple of years after the issue 

 of the June 1863 number of the ' Annals ' from which the 

 above paragraph was taken, it was proved by me, not, as 

 Prof. Leidy observes at p. 279 of his work, " in one in- 

 stance," but in a sufficiintly large number of instances 

 to place the point at issue beyond dispute, that Gromia nor- 

 mally possesses both a nucleus and contractile vesicle, and 

 must therefore, in spite of its "■ reticularian " pseudopodia, be 



