1910] CURRENT LITERATURE 389 
or to a pathological nuclear migration, as suggested by CHRISTMAN, which 
Kurssanow has often observed accompanying the normal sexual process. He 
believes the sterile cells, which are equally well formed on all of the fertile ones, 
are not to be regarded as trichogynes. They appear to act only as buffers between 
the epidermis and the fertile cells. He strongly doubts any connection or direct 
relationship of the rusts to the red algae.—J. B. OVERTON. 
Animal ecology.—It is pleasant to note greatly increased activity along ecologi- 
cal lines on the part of zoologists. Contributions that should have been notice 
here long since are found in papers by SHELFORD, RUTHVEN, and HANKINSON. 
SHELFORD?! has considered the relation of tiger beetles to plant succession, and 
has found that there is quite as definite a succession of forms, when the physiog- 
raphy changes, as has been recorded for plants. For example, certain species of 
Cicindela characterize the beach of the dune region near Chicago, while others 
take their place as the dunes develop, and still others as the dunes become 
established. Similar succession stages are given for depressions. No species 
seems to be fitted for life in the climax mesophytic forest of the region 
RUTHVEN,*? after presenting the environmental features of feels regions of 
New Mexico and Arizona together with full descriptions of the animals collected, 
gives an exceedingly interesting summary. It is concluded “that each set of 
environmental conditions which is marked out by a distinct plant association has 
a definite reptile fauna,” and that the sharpest line between the animal associations 
is that corresponding to the line between the pinyon-cedar association and the 
more arid treeless associations. It is also noted that continued denudation may 
be expected to result in the increased development of the arid associations. Plant 
ecologists, who as a class have long recognized the fundamental errors in MER- 
RIAM’s zonal classification as applied to plants, will be interested in observing 
RUTRVEN’s conclusion, based on reptiles and amphibians, that ‘“‘it seems advisable 
hot to stretch any one zone over the entire continent.” The paper is illustrated 
by a number of halftones showing characteristic animals and habitats. 
ANKINSON?3 has given a detailed account of a biological survey of a small 
Michigan lake. F ollowing an account by Davis on the physiography and geology 
of the region, HANKINSON gives a detailed statement concerning the various field 
Stations and their characteristics, nine kinds of habitats being recognized between 
the shore and deep water. After an ecological account of the fish fauna by Han- 
KINsON, Davis treats of the flora and its ecological features, giving a list of the 
* SHELFORD, V. E., Preliminary note on the ei a of the tiger beetles 
ee sid its relalion to plant succession. Biol. B 1907. 
HVEN, A. G., A collection of reptiles and eau from southern 
New Mesc ae Aelia Bull. Amer. Mus. Nat. Hist. 23:483-604 7. 
3 HANKINSON, T. L. , A biological survey of Walnut Lake, ees with chapters 
ae the physiography, geology, and flora of the region by CHarvEs A. Davis, and a paper 
on the aquatic insects of the lake by James G. NEEDHAM. Rep. Mich. Geol. Surv. 
1907215 7-288. 
