746 THE AMERICAN NATURALIST. [VoL. XXXIII. 
After an extensive and valuable discussion of the anatomical 
features of agreement and difference between the five species noted 
above, Zschokke enters upon a critical review of the subfamily 
Anoplocephalinæ. Of family characters the so-called pyriform appa- 
ratus of the inner shell is certainly variable and available at most for 
the determination of species. On the other hand, the presence of 
three shells is clearly distinctive. 
All cestodes yet described from aplacental mammals belong to the 
Anoplocephalinæ, even those which are incompletely known. In 
that family these five species occupy a separate position, being 
clearly distinct from the Anoplocephalinæ of ruminants and certain 
apes, the genera Moniezia, Thysanosoma, Stilesia, from those of many 
perissodactyles and some rodents, the genus Anoplocephala, and from 
those of rodents, the genera Cittotænia and Andrya. There remains 
for their reception only the heterogeneous genus Bertia, and with ° 
this the odesa-edulis-sarasinorum group agrees in main features, con- 
stituting a distinct natural subdivision of the genus. The group 
echidne-semont departs from Bertia, however, in not unimportant 
respects in which it is also unlike all other anoplocephaline cestodes, 
so that a new genus, Linstowia, is formed for these species. Prominent 
among the points characterizing it is the location of the vagina and 
vas deferens ventral to the longitudinal excretory canals and lateral 
nerve trunk, and of the narrow dorsal vessel marginal to the broad 
ventral vessel. In full agreement with repeated utterances of Stiles, 
Zschokke emphasizes here the taxonomic importance of the relative 
position of genital and excretory canals and longitudinal nerve 
trunks. 
The diagnosis of the genus Bertia is rewritten in the light of this 
discussion and its species classed in three groups, of which only a 
single feature need be noted here. (a) Dorsal excretory canals 
remain actually dorsal to the ventral canals. Hosts, apes; species 
B. mucronata and B. conferta Meyner. (b) Dorsal canals lateral to 
ventral. Rodents. B. americana Stiles. (c) Dorsal canals mesal to 
ventral. Marsupials. B. obesa, B. edulis, B. sarasinorum Zschokke, 
and probably also B. plastica Sluiter from Galeopithecus volans. The 
type of the genus, B. studeri R. Bl., and B. satyri are so incompletely 
known that their position, as also the precise form of the genus, 
must remain at present uncertain. 
For the new genus Linstowia, of which a summary diagnosis is 
also given, Z. echidne A. W. Thompson is taken as type, and Z. 
semoni Zschokke also included. Noteworthy is the fact that Lin- 
