1896.] Recent Literature. 567 
of progressive evolution. The author holds that sensation is a cause of 
effects which would not appear in its absence, and that its presence 
conditions progressive evolution. The author holds this to be proven 
not only by the direct effect of consciousness as observed, but also on 
the other ground that there is no sufficiency in the inorganic and un- 
conscious organic energies to effect progressive evolution. This is be- 
cause the well-known tendency of the latter is to the integration of 
matter and the dissipation of energy, which leads always away from 
vital phenomena. The author believes the entire vegetable kingdom 
to be degenerate, its vitality being the expression of automatic energy 
which derived its self-sustaining character from ancestors endowed with 
sensation which oecupied a position between animals and plants. The 
‘Mycetozoa he believes to be existing near relatives of these types. 
The book is illustrated by 120 plates and cuts. One of these illus- 
trative of homoplassy, we extract from the chapter on kinetogenesis, 
with the following explanatory remarks : 
“ Before reviewing the subject, I cite what is the most remarkable 
example of homoplassy in the Mammalia which has yet come to the 
knowledge of paleontologists. Ameghino has discovered in the cenozoic 
formations of Argentina a group of Ungulata which he calls the Litop- 
terna, and which I regard as a suborder of the Taxeopoda, allied to the 
Condylarthra (p. 128). Ameghino placed the group under the Perisso- 
dactyla, but the tarsus and carpus are of a totally different character, 
and indicate an origin from the Condylarthra quite independent of 
that division. The carpal and tarsal bones are in linear series, or if 
they may overlap, it is in a direction the opposite of that which char- 
acterizes the order Diplarthra (=Perissodactyla and Artiodactyla). 
But the Litopterna present a most remarkable parallelism to the 
Perissodactyla in the characters of both the feet and the dentition. No 
genus is known as yet which possesses more than three toes before and 
behind, and these are of equal length (Macrauchenia Owen). In this 
genus the teeth are not primitive, but are much modified. The most 
primitive dentition is seen in the genus Proterotherium (Ameghino) 
where the superior molars are tritubercular, as in many Condylanthra. 
In this genus (PI. X, fig. A) there are three toes, but the lateral ones 
are reduced, about as in the equine genus Anchitherium (p. 148). In 
the next genus, Diadiaphorus Amegh., the superior molars are quadri- 
tubercular and crested, while the lateral toes are reduced still more, 
being quite rudimental (figs. B C), as in the equine genera Hippo- 
therium and Prothippus. The superior molars have not progressed 
so far as in these genera, but are not very different from those of 
