Heview of Recent Geological Literature. 259 
originally produced it. From this it would also be expected that the 
impressed zone would persist in old age forms in which the outer whorl 
becomes free from the coil. This is often found to be the case, as in Eti- 
rystoDiitea kelloggi from the Quebec group. It is less noticeable in the 
ammonoids, for many old age forms return to the normal cylindrical 
form of the tube soon after the whorls become free. 
The Weissmannian school deny that acquired characters are inherited, 
but the results of the studies here briefly described show the contrary. 
"It is practicable to isolate inherited characters from new variations 
which have not become fixed in any phylum. It is also practicable to 
point out characters which are transient in various ways appearing in 
individuals but not in varieties, in species but not in genera, and so on. 
When one has by this system of exclusion arrived at the end of the list 
he finds that there is no class of characteristics which may be described 
as non-inheritable. The new variations of any one horizon which can 
be isolated from the inherited ones are not distinguishable in any way 
from others which occurred previously. Later in time these new varia- 
tions in their turn become incorporated with the younger stages of de- 
scendants. The transient characters of the zoon also do not differ in 
any way from others that are inherited in allied species, genera, etc." 
"All characteristics, even those observable in some groups only in old 
age, are found in the adults of other groups and finally in the young of 
the descendents of these, according to the law of tachygenesis. Every- 
thing is inherited or is inheritable, so far as can be judged by the be- 
havior of the characteristics." In conclusion: "These cumulative re- 
sults favor the theory of tachygenepis [earlier inheritance] and diplo- 
genesis [acquired and hereditary] and are opposed to the Weissmannian 
hypothesis of the subdivision of the body into two essentially distinct 
kinds of plasm, the germplasm, which receives and transmits acquired 
characteristics, and the somataplasm, which, while it is capable of ac- 
quiring modifications, either does not or cannot transmit them to de- 
scendants." 
How much more satisfactory and conclusive are the results obtained 
through the historical study or a character manifestly acquired by me- 
chanical necessity and running through long geological ages than to 
attempt similar results by cutting off the tails of mice and expecting to 
produce a breed of anurous Musi So far as known to the reviewer, pro- 
fessor Hyatt has given the most complete scientific demonstration of 
the inheritance and phylogeny of an acquired character. c. E. b. 
Structure and Appendages of TrinucleuB. By C. E. Beechek. (Am. 
Jour. Science, vol. xlix, p. 307, pi. iii, 1895.) From the study of a ser- 
ies of specimens of Trinncleiis concentricus Eaton, found associated 
with Triartlirus becki Green, in the Utica slate near Rome, N. Y., the 
author shows that, in young conditions, distinct ocular ridges terminat- 
ing in an ocular node are present, though in this species of the genus 
they become atrophied at maturity. This structure brings the genus 
into relationship with Harpes, whose eyes are ocelli and situated upon 
the fixed cheeks, very distinct from the structure of the visual organ in 
