115 



Fig. 51a. Diagram showing how blood passes to renal 

 filaments by vessels crossing the lumen of 

 the renal organ. 



Fig. 52. T.S. Renal filaments, x 200. 



Fig. 53. T.S. Secondary lamella, x 200. 



Fig. 54. Male gonad and ducts with penis. x 1. 



Fiff. 55. Female gonoducts. x 1. 



Plate VIII. 



Fig. 56. Section of tubule of testis showing formation 



of spermatozoa. x 1„ 

 Fig. 57a. Spermatid. 



Fig. 57b. "Hair-like" spermatozoon ) , 

 Fig. 57c. " Worm-like " spermatozoon J 

 Fig. 58. Transverse section of ovary. Very slightly 

 magnified. 



Fig. 59. Transverse section of vaginal part of oviduct. 



Slightly magnified. 

 Fig. 60. Transverse section of ovary. x 150. 

 Fig. 61. Under surface of egg capsule showing pore of 



escape. x 1. 



Fig. 62. Early stage in development of larva after 

 cannibalism (after Koren and Daniellsen). 



Fig. 63. Very early larval stage, otocysts present, 

 (after K. and D). 



Fig. 64. Late veliger larva (original). x 50. 



Fig. 65. Egg capsules. Slightly reduced. 



Fig. 66. Shells of young Buccinum at time of departure 

 from egg capsules. x 10. 



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