404 ANNUAL OP SCIENTIFIC DISCOVERY. 



arc to 1)0 found in the nature of their aliment, and in the method of its intro- 

 duction. For whilst the prolopliyte obtains the materials of its nutrition from 

 the air and moisture that surround it, and possesses the power of detaching 

 oxygen, hydrogen, carbon, and nitrogen from their previous binary com- 

 pounds, and of uniting them into ternary and quarternary organic compounds 

 (chlorophyll, starch, albumen, etc.), the simplest protozoan, in common with 

 the highest members of the animal kingdom, seems utterly destitute of any 

 such power, and depends for its support upon organic substances previously 

 elaborated by other living beings. Further, whilst the protophyte obtains 

 its nutriment by simple imbibition, the protozoon, though destitute of any 

 proper stomach, extemporizes, as it were, a stomach for itself in the substance 

 of its body, into which it ingests the solid particles that constitute its food, 

 and within which it subjects them to a regular process of digestion. Hence 

 these simplest members of the two kingdoms, which can scarcely be distin- 

 guished from each other by any structural characters, seem to be physiologi- 

 cally separable by the mode in which they perform those actions wherein 

 their life most essentially consists. The general character of the group of 

 marine rhizopods, commonly termed Foraminifera, was next described; and 

 the lecturer dwelt much on the importance of making great allowance, in the 

 systematic arrangement of their forms, for the very Avide range of variation 

 that may present itself within the limits of one and the same specific type. 

 It is very easy to select from any extensive collection of Foraminifera, recent 

 or fossil, sets of forms having certain characters in common, but yet so dis- 

 similar in other respects, that few naturalists would have any doubt as to 

 their specific, or even generic, distinctness; yet, when the collection is thor- 

 oughly examined, such a series of intermediate forms is found to exist as 

 connects all these by gradations so insensible as to prevent the possibility 

 of any line of demarcation being satisfactorily drawn between them. Re- 

 markable illustrations of this principle were adduced, not only from the lec- 

 turer's own researches, but from Prof. Williamson and Mr. W. K. Parker, 

 on the groups which they have particularly studied; so that it would appear 

 as if this type of animal existence were specially characterized by its ten- 

 dency to such variations. And this will seem the more probable, when it is 

 considered how little of definiteness there is in the form and structure of the 

 sarcode-body that forms the shell ; so that the wonder is, not that there 

 should be a wide range of variation both in the form and in plan of growth 

 of the aggregate body, and in the mode of communication of the individual 

 segments, but that there should be any regularity or constancy whatever. 

 But it is only in the degree of this range that this group differs from others; 

 and the main principle, which must be taken as the basis of its systematic 

 arrangement, that of ascertaining the range of specific variation by an 

 extensive comparison of individual forms, is one which finds its application 

 in every department of natural history, and is now recognized and acted on 

 by all the most eminent zoologists and botanists. There are still too many, 

 however, who are far too ready to establish new species upon variations of 

 the most trivial character, without taking the pains to establish the value of 

 these differences, by ascertaining their constancy through an extensive series 

 of individuals, thus, as was well said by the late Prince of Canino, "de- 

 scribing specimens instead of species," and burdening science not only with 

 a useless nomenclature, but with a mass of false assertions. It should be 

 borne in mind that every one who thus makes a bad species, is really doing 

 a serious detriment to science; whilst every one who proves the identity of 



