538 /. PERCY MOORE. 



EXPLANATION OF PLATE XXXL 



Fig. 25. Terminal portion of one of the anterior pair of vasa deferentia, from 

 a preparation of the fresh material. X 500. ml, ml, limit of muscular layer, be- 

 yond which point are seen epithelial cells only; mn, nuclei of muscle fibres; 

 /, lumen. 



Fig. 26. Oblique section across the upper part of the copulatory bursa, ap- 

 proximately through the plane indicated by a, a in Fig. 19, and b, b in Fig. 20, 

 from a preparation stained in Kleinenberg's haematoxylin. X 500. The right 

 side of the figure reproduces the camera tracings unchanged, the left attempts to 

 depict the appearance of the section. Im, longitudinal, and tm, circular muscle 

 coats ; be, epithelial lining of bursa, passing into the glands at two opposite points ; 

 Po, outer coat of the projecting end of the retracted penis {Po is made up of epithe- 

 lium, circular, and longitudinal muscle fibres just above the plane of the section, 

 but these were obscure in the specimen figured) ; ses, sub-epithelial space ; Pi, cir- 

 cular muscles of the beginning invagination which forms the penis proper; Pe, 

 penis epithelium ; PI, lumen. 



Fig. 27. Small anterior portion of a longitudinal section through the ovary 

 of a mature individual. Stained in Biondi-Ehrlich. X 500. 6" 6-7, muscular septa 

 6-7. 



Fig. 28. Portion of a transverse section through the 7th somite of B. philadel- 

 phicus, showing the entire length of the left ovipore. Klein, haem. X 500. 0, a 

 mature ovum; n, its nucleus; oe, epithelium of ovipore passing into the perito- 

 neum ; cm, circular muscle fibre, between two of which the external opening is situ- 

 ated ; Im, longitudinal muscles ; eg, clitellar glands. 



Fig. 29. Reconstruction (from camera tracings of a series of transverse sec- 

 tions) of a spermatheca, seen from behind. Klein, haem. X 195. ep, external 

 opening lined by columnar epithelium ; gl, posterior one of the pair of glands ; 

 slm, external layer of (longitudinal) muscle fibres, present on proximal portion 

 only; i, inner, and 0, outer limb ; bn, longitudinal muscles of body walls; n, nerve 

 cord. 



Fig. 30. Transverse sections of the inner limb of a spermatheca near its blind 

 end. The muscle fibres are here cut obliquely or transversely, owing to their 

 spiral disposition. The appearance of the inner and outer zones in the epithelial 

 cells is shown, and the several nucleoli and indications of an intra-nuclear net- 

 work. Haem. X 840. 



Fig. 31. Omitted. 



