Fig. 59 A. Section through the inner aspect of a portion of the testis and mesorchium, to shew the network of the vasa efferentia (_nve_) becoming continuous with the seminal tubes (_st_). The granular matter nearly filling the vasa efferentia and the seminal tubes represent the spermatozoa. Fig. 59 B. Section through part of the kidney and its duct and the longitudinal canal (_lc_) at the base of the mesorchium. Canals (_sc_) are seen passing off from the latter, which enter the kidney and join the uriniferous tubuli. Some of the latter (as well as the seminal tubes) are seen to be filled with granular matter, which we believe to be the remains of spermatozoa. Fig. 60. Diagram of the urinogenital organs of the left side of an adult female example of _Lepidosteus_ 100 centims. in length. This figure shews the oviduct (_od_) continuous with the investment of the ovary, opening at _od´_ into the dilated part of the kidney duct (segmental duct). It also shews the segmental duct and the junction of the latter with its fellow of the right side to form the so-called bladder, this part being represented as cut open. The kidney (_k_) and lymphatic organ (_ly_) in front of it are also shewn. PLATE 40. Fig. 61. Transverse section through the developing pancreas (_p_) of a larva 11 millims. in length. Fig. 62. Longitudinal section through portions of the stomach, liver, and duodenum of an embryo about a month after hatching, to shew the relations of the pancreas (_p_) to the surrounding parts. Fig. 63. External view of portions of the liver, stomach, duodenum, &c., of a young Fish, 11 centims. in length, to shew the pancreas (_p_). Fig. 64. Transverse section through the anterior part of the trunk of an embryo, about a month after hatching, shewing the connection of the air-bladder with the throat (_ab´_). Fig. 65. Transverse section through the same embryo as fig. 64 further back, shewing the posterior part of the air-bladder (_ab_). Fig. 66. Viscera of an adult female, 100 centims. in length, shewing the alimentary canal with its appended glands in natural position, and the air-bladder with its aperture into the throat (_ab´_). The proximal part of the duodenum and the terminal part of the intestine are represented as cut open, the former to shew the pyloric valve and the apertures of the pyloric cæca and bile duct, and the latter to shew the spiral valve. This figure was drawn for us by Professor A. C. Haddon. PLATE 41. Fig. 67. Transverse section through the tail of an advanced larva, shewing the neural and hæmal processes, the independently developed interneural and interhæmal elements (_is_), and the commencing dermal fin-rays (_df_).