Dv. Wallich on the Amoebae. 217 



few brief extracts from Prof. Leidj's work already referred 

 to, and from a paper of Prof. Martin Duncan, showing how 

 far these two eminent authorities were acquainted with my 

 writings of 1863-64 : secondly, to furnish such extracts from 

 Dr. Gruber's two papers as may suffice to indicate clearly 

 those observations and statements of his that I desire to 

 criticize or controvert ; thirdly, to furnish such extracts from my 

 own papers in the ' Annals,' above referred to, as may be 

 needed to prove that my claim to priority is literally and 

 fully substantiated ; and, lastly, to conclude with some general 

 observations. 



Prof. Leidy. — " It appears from the researches, especially 

 of British authorities such as Carpenter, Williamson, Wallich, 

 Brady, Parker, and Jones, that the members of this class are 

 infinitely variable, and that, indeed, no absolute distinctions 

 of species and genera exist, such as appear more definitely to 

 characterize the higher forms of animal life. My own inves- 

 tigations rather confirm this view, and under the circum- 

 stances we can only regard the more conspicuous forms as so 

 many nominal species, in likeness with the species of higher 

 organic forms more or less intimately related, or by inter- 

 mediate forms or varieties merging into one another." 

 — Freshwater RMzopods of North America (Washington, 

 1879), p. 6. 



" Dr. Wallich regards the endosare and ectosarc as tem- 

 porarily distinct portions of the sarcode, mutually convertible 

 into one another. The ectosarc becomes differentiated from the 

 endosare by contact with the outsidemedium in which the animal 

 lives, and from time to time reverts again to the condition of the 

 more fluent endosare within. From this view, as intimated by 

 Dr. Wallich himself, the ectosarc is due to a temporary and 

 partial coagulation of the endosare coming into contact with 

 the water in which the animal lives, and again reverts to the 

 condition of the more fluent endosare as it retreats to the mass 

 of the latter within the body. This process reminds one of 

 the cooling of a molten mass of metal at the sides of a cru- 

 cible, and the melting away of the crust as it is stirred from 

 the sides of the molten mass within." — Op. cit. p. 24. 



" Dr. Wallich considers the so-called vacuoles or food- 

 vacuoles not in the light of mere spaces, but as temporary 

 vesicles of ectosarc, due to inversion of portions of the exterior 

 ectosarc at the time of the inception of the food, or to the con- 

 tact of water with portions of the endosare."— /i^ic^, p. 26. 



" While there is no absolute distinction between the ecto- 

 sarc and endosare" (reference here made to A. Proteus) j 

 " the two being continuations of the same protoplasmic mass, 



