goo THE AMERICAN NATURALIST.  [Vor. XXXIV. 
more than six hundred species in every branch of the animal king- 
dom and which shows clearly by the number of entries — 91 under 
Vermes, 121 under Hexapoda, 95 under Pisces, and 93 under Aves 
— what groups are particularly infested by these parasites. An 
alphabetic index of genera and species completes the work. The fact 
that, as entered on the last page, the manuscript was closed in 
December, 1897, while the title-page bears the imprinted date of 
July, 1899, goes far to explain certain shortcomings in the work, for 
our knowledge of this group has been particularly widened by some 
very recent contributions. An additional difficulty in the treatment 
of these forms is to be seen in the record of 94 known and 29 doubt- 
ful genera, embracing 239 certain and 259 doubtful species, as given 
by the author at the opening of the systematic part. 
The system employed by Labbé is as follows: 
I. Legion Cytosporidia (spore wanting or without polar capsules). 
I. Order Gregarinida (sporulation not intracellular). 
4. Suborder Cephalina. 
a. Tribe Gymnosporea. 
6. Tribe Angiosporea. 
. Suborder Acephalina. 
2. Order Coccidiida (sporulation intracellular ; no motile free stage in 
adult form). 
A. Suborder egy (many archispores). 
a. Tribe P. digeni 
6. Tribe P. monogenica. 
B. Suborder Oligoplastina (few archispores). 
a. Tribe Tetrasporea. 
3. Order Hemosporidiida (sporulation intraglobular). 
4. Order Gymnosporidiida (adult ameeboid ; no cyst). 
II. Legion Myxosporidia (spores with polar capsules). 
I. Order Phznocystida (polar capsules distinct). 
2. Order Microsporidiida (capsules invisible in life). 
Sporozoa incerte sedis: Sarcosporidia, 
Amocebosporidia, 
Serumsporidia. 
A number of genera, including Amcebidium, Piroplasma, and Babe- 
sia, are listed as Sporozoa incerta, while Coccidioides and the pseudo- 
Coccidia are included in an appendix. 
It is not to be expected that a group including so many poorly 
known forms and so many species, genera, and even possible orders, 
