Reviews—Professor J. W. Gregory's Fossil Bryozoa. 323 
are often restricted in their range of distribution, and thus of value 
as zonal fossils. The view formerly held that their specific life was 
prolonged and that consequently they were of little or no use in 
marking zones was due to unreliable determinations of species. 
The Systematic Description in this volume includes first the 
Cretaceous Cyclostomata which were not treated in the first volume. 
Of these the families belonging to C. Tubulata are the Crisiide, 
Theonoide, Fascigeride, and Osculiporide, and to C. Cancellata the 
family of the Desmeporide. The families included in the order 
Trepostomata are the Cerioporide, Heteroporide, Zonatulidee, Radio- 
poride, and Cameroporide. In the sub-class Phylactolemata the 
family Plumatellide. There are also additions and corrections to 
the following families of the Cyclostomata which were described in 
the previous volume: Diastoporide, Idmonide, Entalophoride, Eleidee, 
Horneride, Petaloporide, and Clauside. 
In the descriptions of species the same lines are followed as in the 
earlier parts of the Catalogue; there is first a full Synonymy, then the 
Diagnosis, Dimensions, Distribution, Figures, and Affinities of the species. 
Then follows a List of the Museum Specimens of the particular species 
described, giving the registered number and details of form and size 
of one or more specimens included under this number; the formation, 
zone, and locality whence they come; and lastly, the name of 
the donor or of the collection to which they formerly belonged. 
Occasionally the specimens under one number are so many as to 
preclude any attempt to refer to them individually—for example, in 
“TD. 3367. More than 100 specimens ’”’. 
Dr. Gregory includes in the Catalogue descriptions or references to 
all known species of Cretaceous Bryozoa, whether represented or not 
in the Museum Collection, and altogether in this volume 308 species 
belonging to 67 genera are enumerated. But of this number the 
collection possesses specimens of only 103 species and 88 genera. 
Some of the unrepresented forms are known to be of a dubious 
character, and others may possibly be found in the recently acquired 
materials not yet fully examined; but allowing for these, it would 
seem that there are many significant gaps in the collection yet to 
be filled up. 
A very useful List of Chief Localities for Cretaceous Bryozoa 
(excluding England) and a comprehensive Bibliography are appended. 
The Subject Index and the carefully drawn up Index to systematic 
names of Bryozoa afford every facility for reference to the forms 
described. The figures in the nine plates are excellently drawn ; 
a greater number of plates to allow of further illustrating the interior 
structure of some of the forms, more particularly of the Trepostomata, 
would have been desirable. 
Students of fossil Bryozoa are greatly indebted to Dr. Gregory and 
to those who have helped him in the preparation of this and the 
previous volume on the Cretaceous forms, and they will hail with 
satisfaction the early completion of the final volume now in the 
capable hands of Mr. W. D. Lang. 
