1908.] 



ASPIDOBRANCH GASTROPOD MOLLUSCS. 887 



Plate LX. 



Fig. 50. The male organs of K. {Faranerita) gagates, semi-cliagrammatic. 



51. A similar representation of the male organs of Nerita lineata. 



52, Part of a section through the outer wall of the terminal chamber of the 



male ducts of N. {Faranerita) variegata, illustrating the formation of 

 bunches of unicellular glands in the connective tissue underlying the 

 epithelium of the chamber. X about 1000. 



Plate LXI. 



Fig. 53. Part of a section through the inner wall of the tenninal chamber of the 

 same species, showing a bunch of unicellular glands the ducts of which pass 

 between the ciliated epithelial cells lining the chamber. X about 1000. 



54. Part of a section through the prostate of the same species, showing the 



glaud-cells and ciliated interstitial cells {cil.c). X about 1000. 



55. Part of a section through the terminal coils of the epididymis of the same 



species, showing the tube filled with spermatozoa and the granular non- 

 ciliated, cells (ej3.) lining the tube. 



Plate LXII. 



Fig. 56. Part of a section through the basal gland of the male organs of the same 

 species, showing groups of gland-cells containing vesicular bodies, each 

 with a brightly staining spot. 



57. a, h, c, d, e. Different forms of concretions from the crystal sac of Nerita 



melanotraga. 



58. A diagram illustrating extent and relations of the coelom in Faranerita. 



59. Reticular connective tissue and metabolic cells from Neritina fluviatilis, 



X about 1000. ret. Protoplasmic reticulum with nuclei, met. Metabolic 

 cells with granules. 



Plate LXIII. 



Fig. 60. The female organs of iV. {Faranerita) gagates. semi-diagrammatic. This 

 figure, as also figures 64 and 65, represent the organs as they appear when 

 dissected from the ventral surface. The ootype and rectum, which in their 

 natural position lie dorsad of and partly to the left of the vagina, are 

 thrown over to the right side of the figure. 

 61. A longitudinal section through the anterior part of the genital complex of 

 N. {Faranerita) variegata, showing the vaginal aperture and the aperture 

 of the ductus enigmaticus. 



Plate LXIV. 



Fig. 62. A section from the same series through the middle of the genital complex. 



63. A section from the same series through the lower part of the genital 



complex. 



64. A drawing of the vagina and spermatophore-sac of -A^. {Faranerita) longi- 



spina : the spermatophore-sac has been laid open. 



Plate LXV. 



Fig. 65. A semi-diagrammatic representation of the female organs of Nerita 

 plicata. 



66. A section of a sperraatophore oi Nerita plicata. I. Central capsule filled 



with spermatozoa. II. Chitinous wall of the central capsule. III. 

 Layer of protoplasm with chromophilous granules. IV. Radiating fibres. 

 V. External wall. 



67. A transverse section passing through the bottom of the fundus of the 



ootype G^ Nerita plicata, illustrating the relations and structure of the 

 sperm-sac. For further description see pp. 870 & 871. 



Plate LXVI. 



Fig. 68. A section from the same series as fig. 67, taken at a higher level and 

 showing the connection of the thalamus with the fundus of the ootype. 

 69. A spermatophore of Nerita plicata. 



