Prof. E. Claparéde on the Structure of the Annelida. 345 
and cellular (coriwm, Rathke, derme, Quatref.), corresponding 
with the subcuticular or chitinogenous layer of the other Arti- 
culata; the other extra-cellular, the cuticle (epidermis, Rathke 
& Quatref.), sometimes very delicate, sometimes composed of a 
thick layer of chitine. The integuments have hitherto been 
studied with care only by M. Kolliker, to whom we are also 
indebted for several other excellent works on the histology of 
the Annelida, works all of which have unfortunately remained 
unknown to the author of the ‘ Histoire Naturelle des Annelés,’ 
The superficial layer deserves the name which has been given 
to it by M. Kolliker.. From a histogenetic point of view it falls 
perfectly under the category of cuticular formations. The sub- 
cuticular layer (hypodermis, Weism.) which secretes it may often 
be denominated, as it is by M. Kolliker, an epithelium ; however, 
in most cases it is impossible to recognize the limits of its con- 
stituent cells. The nuclei seem rather to be scattered in it with 
considerable regularity in a continuous granular stratum, as has 
been seen by M. Baur im certain Arthropoda. Wherever the 
cuticle attains a certain thickness, it presents two systems of 
strie at right angles (or more frequently about 70°), which have 
been already well observed by M. Kolliker*. The tubular pores 
(Porenkandile of the Germans), when they exist, are distributed ~ 
in lines congruent with these strie. M. Kolliker has been 
struck by the distance which separates these pores from each 
other. Frequently, he says, not more than one of them corre- 
sponds with each subjacent cell; and he asks whether these 
apertures are really the homologues of the tubular pores (Poren- 
kandle) of the Arthropoda, or whether they may not rather be 
compared with apertures of the cutaneous glands, such as those 
discovered by M. Leydig in the Piscicole, or with the hairs of 
Insects and Crustacea. To this question I can reply positively 
that the two categories of pores exist in the Annelida. Those 
which serve for the discharge of certain secretions seem to exist 
in all species. Sometimes, especially in the large species, they 
attain a considerable diameter; but usually they are very wide 
apart. Sometimes, however, we find them brought together in 
groups or islets. The canalicular pores are much smaller and 
much closer together, and do not correspond with glands. They 
occur only in the species with a thick cuticle, and not even in 
all these. I shall describe some examples in detail, especially 
among the Hunicea. Wherever these very fine and approximated 
* M. de Quatrefages, to whom these striz are not unknown, sees in them 
the indication of two systems of fibres—an opinion which may be provi- 
sionally admissible in the case of certain worms. Jn any case the learned 
Academician with justice attributes to these strie the iridisation of the 
surface of the body in many Annelides. 
