STUDIES ON EARTHWORMS. 103 



not very freely given. The various layers of the body wall are 

 considered, and a discussion of the opinions of previous authors 

 with respect to each of the layers, forms a great part of the 

 paper. In the epidermis he describes the columnar cells and 

 the goblet-cells; but in the latter he figures no branched 

 base, which, however, I find to exist : the structure of the 

 clitellum is not described. 



Below the epidermis he finds a " basal membrane.^^ In the 

 muscular layers he notes an appearance presented in sections 

 across the fibres, which shows the fibre to be made up of 

 fibrillse. The fibre consists of a denser peripheral portion, in 

 which lies the nucleus, and a less dense central portion. The 

 bundles of muscle-fibres are surrounded by finely granular 

 connective tissue, the perimysium, in which are found small 

 nuclei, whilst the larger nuclei belong to the muscle-fibres. 



He draws attention to the fact that the arrangement of the 

 longitudinal muscles in Lumbricus agricola, HoflFm.j is 

 not universal in the genus. 



The dorsal pore lies on the anterior edge of the somites in 

 which it occurs, and appears in the intersegmental groove. It 

 is absent in the most anterior somites, but the position of the 

 first pore is constant for a given species, e. g. in L. agricola, 

 between somites viii and ix, in Allolobophora turgida, 

 Eisen, between somites x and xi. In Typhseus orientalis, 

 Beddard, the pore commences only behind the clitellum. It 

 has not been noticed in Anteus, Titanus, Urochseta, or 

 Microchseta. 



Vejdovsky states that it is generally absent in the Limi- 

 colse. 



In a fully-developed clitellum the pores become closed by 

 a development of cuticular substance around the edge, which 

 gradually increases and fills the pore. In Allol. mucosa, 

 Eisen, however, it remains visible in the clitellum. 



Claparede described the epidermis as being invaginated at 

 the dorsal pore, as it is at the seta-follicle ; but Ude finds 

 that such is not the case. The dorsal pore is a perforation 

 through the epidermiis and muscular layers, and the coelomic 



