On an Australian Land Nemertine. 91 



veiy inncl) tliinner than in its normal condition, while the 

 component cells are mucli more difficult to make out. 



In favourable preparations, however, the e})idermis is 

 seen, very cleai-h^ indeed, to consist of very slender, greatly 

 elongated, c>)lunniar cells, placed closely side by side. 

 (Fig. 9, ep) Each cell is broadest at its outer end and 

 tapers gradually to a fine point imbedded in the subjacent 

 tissue. About the centre of each is an elongated, deep- 

 staining nucleus. The outer surface of the epidermis is 

 richly ciliated. 



Beneath the e])idermis is a well-developed layer of uni- 

 cellular glands (Fig. 9, (jl. c.) The gland-cells are pear- 

 shaped, with the narrow ends pointing outwards. Each 

 contains a small nucleus and a larger or smaller quantity of 

 finely granulai- material. These gland-cells are much more 

 numerous and contain much more of the granular contents, 

 on the doi'sal than (m the ventral aspect of the body. There 

 can, I think, be no doubt that the}^ secrete part of the 

 slime with which the surface of the body is covered. 



Scattered between the gland-cells and amongst the tails 

 of the epidermic cells are numerous small, darkly staining 

 nuclei (Fig. 9, na), whose exact relations I have not been 

 able to make out. Around and beneath the gland-cells we 

 also see a quantity of very finel_y granular material which 

 scarcely stains at all with borax carmine and which extends 

 inwards to the circular muscle layer. This tissue (Fig. 9, 

 I), m.), in which a few scattered nuclei are imbedded, 

 evidently constitutes the basement membrane already 

 frequently described by writers on Nemertean anatomy. 



h. Muscular System. 



Within the basement membrane there are twoj well- 

 developed muscular sheaths completely investing the body, 

 viz., an outer sheath of circularl}" disponed muscle fibres and 

 an inner sheath of longitudinal ones. Between these two 

 principal sheaths there is a very thin and delicate la3-er 

 of diagonally disposed muscle fibres. 



The outer, circular, muscle sheath (Figs. H, 7, 8, 9, 10, 

 V. 7)1.) is well developed and of about equal thickness all 

 round the bod}^ it is not, however, nearly so thick as the 

 longitudinal sheath. 



The inner, longitudinal muscle sheath (Figs. 6, 7, 8, 9, 10, 

 /. m.) is more strongl}' developed on the venti-al than on the 



