M. A. de Quatrefages on the Classification of the Annelides. 7 
motion, in the first place sets completely on one side the very 
exceptional type of the Polyophthalmea. The remaining twelve 
families represent the type of the A. erratice in all essential 
points. 
These twelve families are themselves divided into two groups, 
remarkably distinct in many respects, although the table only 
indicates one difference, that presented by the armature of the 
mouth. The Hunicea and Lumbrinerea on the one hand, and 
on the other the ten other families, present, from an anato- 
mical point of view, such marked contrasts, that it will probably 
some day be necessary to represent them in the classification 
itself, by forming a separate suborder with the two families 
just mentioned. Thus, to cite only a very striking fact, I will 
mention that, according to investigations of my own already of 
an old date, the stomatogastrie nervous system originates upon 
the cerebrum itself in the Hunicea and Lumbrinerea, whilst it 
issues from the connective in the Neretdea, the Nephthydea, the 
Phyllodocea, the Glycerea, &c. The digestive apparatus pre- 
sents equally remarkable differences, extending not only to the 
armature, but even to the organization of the trunk. 
The ten families with the buccal armature simple, or none, also 
divide into some well-marked secondary groups. Of these, 
the Glycerea alone form one. In them the head seems to at- 
tempt a repetition of the body on a small scale, and in the 
opposite direction. It is composed of more or less numerous 
segments, and thus departs completely from the ordinary type. 
It may be remarked that this morphological modification hke- 
wise coincides with very interesting anatomical peculiarities, 
among which I shall limit myself to citing the presence of dis- 
tinct globules in the blood, the existence of branchize of an ex- 
ceptional structure, the almost complete absence of inter- 
annular diaphragms, &c. 
The Glycerea set on one side, we find two groups very dis- 
tinctly characterized by the presence and absence of branchi. 
A perfectly similar fact had already presented itself in the group 
of Krraticee with the buccal armature complicated. But, in the 
the latter, the disappearance of the branchize may be regarded 
as a simple fact of organic simplification coincident with others 
bearing especially upon the vascular apparatus. The type, 
moreover, remains the same in the arrangement of the nervous 
system and digestive apparatus. In point of fact, the Lwm- 
brinerea are degraded Eunicea. It is otherwise with the Er- 
raticee with a simple buccal armature. We cannot, for ex- 
ample, regard the type of the Nereidea as derived by degrada- 
tion from the type Nephthys ; for the former, in all respects equal 
to the latter, is superior to it in some particulars (such as the 
