of England and India, 19 



in this way, we shall never be able to get on without much con- 

 fusion either in describing them or in distinguishing their spe- 

 cies. Mere descriptions at this period of their history will not 

 suffice, as those of Schlumberger testify (Ann. des Sc. Nat. t. iii. 

 p. 254, 1845), especially where a single or only a few specimens 

 of the species have been obtained, because numbers are required 

 for comparison, to establish a species ; and although a figure may 

 not be absolutely necessary with a great number of specimens of 

 the same species, it, for the same reason, becomes absolutely so 

 with one or only a few of it. It is only by numbers that we can 

 arrive at the typical form of the species, here as well as in the 

 Rhizopoda generally, where those who are well acquainted with 

 them know that the varieties are almost infinite. 



Appended to the descriptions will also be found "Observa- 

 tions," in which any structural or physiological fact bearing on 

 the species only, or in connexion with the Rhizopoda generally, 

 that appeared to me deserving of notice, has been mentioned. 

 This is particularly the case under Difflugia compressa, a new 

 and interesting species, which has been found so abundantly 

 that I have been able to make out almost as much about it as 

 about D. pyriformis. 



Amceba. 

 Amceba princeps, Ehr. 



This species often occurs in Bombay as well as in Europe, and 

 often with the villi on the posterior extremity, first pointed out by 

 Dr. Wallich. I have given a description and illustrations of it 

 (Annals, 1863, vol. xii. p. 30), chiefly for the purpose of pointing 

 out the occasional presence in it of certain cells which appear to 

 me to be reproductive elements ; and have nothing more to add 

 concerning it here, saving allusion to the corrections or altered 

 views respecting the nucleus, which will be found at page 254 

 of the same volume. 



Amoeba quadrilineata, Cart. (Annals, 1856, vol. xviii. pi. 5. f. 3) ; 

 A. radiosa (?), Duj. {ibid. figs. 10-16) ; and A. verrucosa, 

 Ehr., Annals, 1857, vol. xx. pi. 1. fig. 12. 

 I have already figured these as they occur in Bombay. A. 

 radiosa was only thus named provisionally; but since I have 

 returned from India, and have seen Auerbach's paper on the 

 Amoebce (Zeitschrift fiir wissenschaftl. Zoologie, Dec. 31, 1855), 

 which just preceded my own in publication, it seems evident to 

 me that this species would be better termed A. bilimbosa, which 

 Auerbach has figured as a new species. 



Another Amoeba to which I should allude here is that which 

 I have delineated with the last-mentioned, and have also pro- 



2* 



