388 REVIEW. 
We have not space here to do more than glance at the 
morphology of the “ cephalic region,” as expounded by our 
author, which is the name he gives to the kopflappen and 
mundsegment of Grube taken together. All Annelids possess 
this “‘ head,” though in some of the sedentary forms it can 
only be distinguished by its appendages, while in the 
Errantia it is highly developed. The two parts of the head 
already distinguished by Grube and others he re-names, the 
first as “lobe cérébral,”’ “ téte,” or “caput,” the second as 
“‘anneau buccal” or “ annulus buccalis.”” The names given 
by Professor Huxley to the same parts are respectively 
* prostomium ” and “ peristomium,”’ names which we cannot 
but hope will be in the end generally adopted, as they have 
been already to some extent in Germany, since they express 
in the neatest form the most important relations of these two 
parts of the worm. The nomenclature of the appendages of 
the head is, M. de Quatrefages says, unsatisfactory, since 
appendages receive the same name in different Annelids 
which receive totally different nerves, and vice versd. He 
considers that the distribution of the nerves should be 
made the criterion of homology in these parts in different 
genera, and we believe that he has here found the only 
test, save that of embryological relationship, which can be 
applied to such parts. The theory of the Annelid’s head 
is In many ways analogous to that of the vertebrate skull. 
The term “antenn”’ is limited by our author to the append- 
ages which are placed on the head properly so-called (kop- 
flappen, prostomium) ; it is not always easy to ascertain what 
appendages are “ placed on” the head, but we have a more 
tangible definition in this—“ the antenne receive their nerves 
directly from the brain itself (pree-oral or supra-cesophageal 
ganglia).”” 
The name “tentacula” is reserved for those appendages 
which proceed from the buccal ring; these receive their 
nerves from the ganglia of the ‘‘ connective”’ or “ accessory 
connective ”’ (pharyngeal commissures). 
The term “ cirrhi tentaculares”’ is used to designate the 
appendages of the first feet when they assume the characters 
of the more strictly cephalic segments; these receive their 
nerves from the ventral chain of ganglia. 
While these considerations are of value in recognising 
equivalent appendages in different genera and families, we 
cannot think M. de Quatrefages’ choice of terms at all happy, 
since it rather tends to create confusion. Let us compare the 
corresponding titles used by different authors. 
