270 The Structure of the Annelids. 



to the present the teguments have only been carefully studied 

 by Kolliker, to whom we owe many excellent papers on the 

 histology of the Annelids, which are unfortunately quite unknown 

 to the author of the " Histoire Naturelle des Anneles." 



" The superficial layer deserves the name which Kolliker has 

 given it. In a histogenetic point of view it belongs entirely 

 to the category of cuticular formations. The subcuticular layer 

 (hypoderm, Weissman) which secretes it — often called with 

 Kolliker epithelium — in most cases does not enable us to recog- 

 nize the boundaries of its constituent cells. The nuclei 

 appear sown with great regularity in a continuous granular 

 layer, as M. Bauer has seen, in certain Arthropoda. Whenever 

 the cuticle attains a certain thickness it is seen to be orna- 

 mented with two systems of striae at right angles to each other, 

 or more frequently at about 70°, as noticed by M. Kolliker. The 

 tubular pores (porenlcanale of the Germans), wherever they exist, 

 are disposed in lines conforming with the striae. M. Kolliker 

 has been struck with the difference of these pores from each 

 other. Often, he says, they correspond only with a subjacent cell, 

 and he asks if these openings are really homologous with the 

 tubular pores of the Arthopoda, and do not rather resemble the 

 openings of cutaneous glands discovered by Leydig in the 

 Piscicoles, or the hairs of insects and crustaceans. To these 

 questions I can reply in a positive manner that both sorts of 

 pores exist amongst the Annelids. Those which serve for the 

 outpouring of certain secretions appear to exist in all species. 

 In large species they are sometimes of considerable diameter, 

 but usually very limited. Sometimes they are found united in 

 groups. The canalicular pores are much smaller, much nearer 

 together, and have no resemblance to glands. They are only 

 found in species which have a thick skin, and not in all of 

 these. . . . The subcuticular layer — the derme of M. 

 Quatrefages — appears always to contain glandular follicles, and 

 that in all parts, even in the cirri and antennas. These follicles 

 empty themselves externally by means of the glandular pores. 

 Some only secrete a thick liquid, others engender bundles of 

 little rods (batonnets), and these I have named bacilliparous 

 follicles ; others only secrete granules/'' 



M. Claparede explains that the bibliography of these bacil- 

 lary corpuscles is very rich, and he wonders that it has altoge 

 ther escaped the notice of M. Quatrefages. " Certain families, 

 he says, " have their teguments literally covered with baccili- 

 parous follicles, even in the cirri and the antennas. This is 

 especially the case with all the Aricians and Spiodians, and a 

 great part of tbe Chsstopterians, Their abundance is likewise 

 remarkable in a crowd of Phyllodocians, and in certain 

 Hesionians. Among the latter especially, their grouping and 





