No. 405.]} REVIEWS OF RECENT LITERATURE. 765 
The authors will invite some criticism because of their extensive 
use of genera and subgenera. Any characteristics which will group 
species must be noticed, but whether or not as much prominence 
should be given many of these groups by giving generic or subge- 
neric names will remain as a matter of opinion. If in this respect 
- the authors have gone to one extreme, they have chosen the more 
scientific one. The retention of common names will prove very 
useful. The type of each genus is indicated, as is also the locality 
of the type of each species. ‘The museum in which the type is 
preserved is also given. 
In the mechanical construction of the book we regret that the 
family and generic names are not at top of the page, as in Bulletin 
No. 16; a useful feature has here certainly been omitted. The 
authors have done well a great work, and Bulletin No. 47, for many 
years to come, will represent the ideas of our.best American ich- 
thyologists concerning the classification of our American fishes. 
: S. E. MEEK. 
The Monascidians of the Bremer Expedition. — The report on 
this group of animals is by Dr. Robert Hartmeyer (Zool. JaArb., 
Abth. f. System. Geog. u. Biologie, Bd. XII (1899), pp. 433-529). 
In all, eleven species are treated, three of which are new. The 
genus Dendrodoa, the validity of which has been doubted by several 
Writers, is accepted by the author and a new species added. 
It is pointed out that, as between the northern and more southern 
range of each species, in every case the latter were taken in the 
greater depths of water. 
The author thinks that the distribution of the species confirms the 
idea of circumpolar range of species. The same writer reported 
some time ago (Zool. Anz., Bd. XXII (1899), Nr. 599, P. 268) that 
the two Arctic species in Dendrodoa of the collection retain the 
larvæ in a brood pouch until a late stage of life. This method of 
larval protection is not uncommon among compound Ascidians, but 
is known in only one or two other instances among the simple ones. 
The author points out that the tendency of Arctic marine animals to 
thus retain the young for protection is seen in various groups; and 
that, consequently, the habit in these two species of Monascidians 
is only in keeping with a general physiological adaptation ; that, 
in all probability, other species will be found to possess the same 
peculiarity. I may add that I have recently observed the same thing 
In a species of Ascidia from Alaskan waters. W. E. RITTER. 
