I20 Cincinnati Society of Natural History. 



numbers and imperfect condition. In many cases species have 

 been founded on single specimens, or two, three, or perhaps half 

 a dozen. It is much easier, naturally, in these cases to formulate 

 specific distinctions, but at the same time, and because of the very 

 sparseness of the material, we become all the more liable to errors 

 of interpretation, which only time and large suites of specimens 

 can correct. 



Species making in palaeontology is largely governed by the 

 individual. If the student has confined his attention solely to 

 geological species, and too many have done so, he will often be 

 unable to comprehend, and be incapable of deciding what amount 

 of difference is required for a new species. Each trivial variation 

 assumes specific importance to him. Individual variation becomes 

 specific, and what a student with a wide knowledge of living forms 

 regards as perhaps of specific value, the mere palaeontologist often 

 calls generic. Th^re is, in fact, no criterion by w^hich to judge 

 fossil species, except individual opinion. We can not see the off- 

 spring of a parent exhibiting variations among themselves as we 

 can in the living world. We can not tell how diversified may have 

 been the forms produced from a single individual ; nor can we 

 prove by testing, how true one species may breed, or whether it 

 will cross readily and produce hybrid offspring with another form. 

 More especially is this the case with the lower forms of animal life, 

 the Bryozoans, the Polyps, or the sponges. But even here the 

 living have an advantage over the dead, for we may see on a 

 single branch, or in a single group, various forms, which found 

 apart, would often be regarded as specifically or even generically 

 distinct. But when, after death, and in a fossil state, these colo- 

 nies, groups or branches become broken up, there is no means of 

 re-uniting them in the form they once had, and we are left to spe- 

 culation and conjecture in regard to the relations of one part to 

 another.* 



*New discoveries arc constantly heingf recorded which show the truth of these re- 

 marks. In Science (IX. 576. Mav 27, 1SS7.) is given an account of a tine specimen of Lepi- 

 dodend) on found in New Yorl<, from which tlie followine: is taken : "It isfitteen feet in 

 lenpth from the roots upward, measures thirteen and a half inches in diaiueter across 

 the base, three inches at the broken upper extremity, and preserves in great beauty and 

 perfection the cicatrices of the leaves, in places the narrow elor.gate, lanceolate foliage 

 and the delicate rootlets." "It is interesting to observe, that, so wide a variation exists 

 at different distances from the base in the arrangement of the cicatrices, one cannot but 

 feel, in examining the fossil, that, it it liad been found in fragments taken from difler- 

 ent spots, it would furnish all the necessary material for a half dozen distinct species of 

 lepidodendron, according to prevalent methods of determining these va'ues. Moreover, 

 toward the base the leaves are uniformly arranged on elevated longitudinal ridges, as iti 

 Sigillaria, showing nothing of the quincunx arrangement hig-her up, and regarded as a 

 diagnostic character of lepidodendron." Evidence of a similar character is given by a 

 writer ill a volume of the Annals of the New York Academy of Sciences. The same 

 thing can be seen in the scars of leaves on the caudex of the living tree fern, the lower 

 ones being quite different in shape from those above. 



