Dr. Wallich on the Rhizopods. 465 



" in form, constitution, and arrangement " the sarcode is as in 

 DiFFLUGIA, &c. ! 



Had my facts and conclusions on the subject been contro- 

 verted, or had sufficient reason been assigned for withholding 

 them, the matter would have been intelligible. But no such 

 case has been made out and no such reasons have been fur- 

 nished. And what has been the result ? Why, that during 

 the last four years the forms specially constituting the subject 

 of this paper have been mentioned in scientific works and 

 journals in this country and abroad associated only with Prof. 

 Leidy's name, and unaccompanied by any accurate characters 

 of importance that had not been already assigned to them in 

 papers published by me fifteen years previously. 



In the bibliographical list appended to my name at the end 

 of the letterpress of Prof. Leidy's work, the following is the 

 sole reference to the transitional forms : — 



"Transition forms, figs. 27 to 33=]SrEBELA COLLAEIS." 



This line furnishes its own commentary *. 



In these circumstances I must be permitted to furnish a 

 somewhat fuller 7'esume of the facts upon which the con- 

 clusions were based which Prof. Leidy summarized as 

 above, since they directly bear on the status of the Neheloi. 

 I must, however, preface what I have got to say by men- 

 tioning that, until very recently, I was unaware of the fact 

 that Prof. Ehrenberg had described and figured an organism 

 under the name of Diffiugia collaris^ which must in all pro- 

 bability have been one of Prof. Leidy's Nebelce, in the ' Pro- 

 ceedings of the Berlin Academy' for 1848 (p. 218). But 

 although very imperfectly described by the eminent German 

 microscopist, no doubt owing to the imperfect lenses then avail- 

 able, his title to priority of discovery ought to be respected just 

 as much as in the case of Diffiugia symmetrica. Nevertheless 

 this fact afiects Prof. Leidy's views and mine on these two 

 genera in very different ways. It adds another powerful reason, 

 in addition to those already furnished, against the transfer of 

 the forms included in them to newly created genera ; in Prof. 

 Leidy's case particularly, since his reference to Ehrenberg's 



* The following errors and omissions in relation to the points under 

 investigation occur in the text of Prof. Leidy's work. At p. 142, under 

 Qundrula, reference is made to "i). proteiformis, var. symmetrica, 'Annals,' 

 1863, pi. X." It ought to be pi. viii. 



At p. 145, under Nehela^ reference made to D. symmetrica, Wallich, 

 ' Annals,' vol. xiii. 1864, pi. xvi. figs. 27-33. No reference to text given, 

 and no reference to paper of Dec. 1863, where same form is described. 



In the same list appended to Nebela no reference at all i* made to the 

 " transition forms." 



Ann. & Mag. N. Hist. Ser. 5. Vol xvi. 32 



