119 



of the same species, only 4 inches long, was also shown, the aido- 

 men of which contained two lobes of enlarged ova, which, to all ap- 

 pearance, would have been deposited in a few days. 



Specimens of males and females oiSyngn. Ophidian, Linn., were also 

 exhibited. In this species neither male nor female possesses an anal 

 pouch, but the ova are carried by the male in hemispheric depres- 

 sions on the external surface of the abdomen, anterior to the anus. 

 All the specimens examined having these external depressions proved 

 to be males, with the testes in the abdomen very obvious : those 

 without external depressions proved to be all females, internally 

 provided with two lobes of enlarged ova. The males of this species, 

 when taken by Mr. Yarrell from the sea, had one ovu7n of the size 

 and colour of a mustard-seed fixed in each cup-shaped depression, 

 but time and the eiFects of a long journey had removed them. Dr. 

 Fleming in his 'History of British Animals,' page 176, states the 

 length of Syngn. Ophidian at about 5 inches : some of Mr. YarreU's 

 specimens measured 9 inches. 



Mr. Yarrell further stated that the males of Syngn. Acus carry 

 their living j'oung in the anal pouch, even after they have been 

 hatched there. He had been frequently told by fishermen that on 

 opening them they had found the living young within the pouch, 

 which they called the belly ; and that if these young were shaken out 

 into the water over the side of the boat, they did not swim away, but 

 when the parent fish was held in the water in a favourable position, 

 the )fOung would again enter the pouch. 



It was observed by M. Agassiz, that the fact of the males of cer- 

 tain species of the genus Syngnathus carrying the ova in a peculiar 

 abdominal pouch, after their exclusion by the female, had been no- 

 ticed on the Continent by Eckstrom, Retzius, and Marcklin ; and 

 that he had himself made the same observation. 



M. Agassiz exhibited drawings of several species of Lepisosteus, 

 together with some of the details of their internal organization ; and, 

 at the request of the Chairman, explained his views with regard to 

 their systematic arrangement and structure, as well as to their rela- 

 tions with various genera of fossil fishes, and the coincidence of some 

 parts of their internal anatomy with that of Reptiles. He described 

 two new species observed by him in the British Museum, taking his 

 characters principally from the form and sculpture of the scales, the 

 presence or absence of the short rays at the base of the caudal and 

 other fins, and the variations in the form and disposition of the teeth. 

 In reference to their internal structure, he particularly called the at- 

 tention of the Meeting to the large and regular sht by which the 

 swimming-bladder communicates with the pharynx ; which he re- 

 garded as bearing even a closer resemblance to the entrance of the 

 trachea of the pulmoniferous Vertebrata in general, than the aperture 

 by means of which the lungs communicate with the pharynx in the 

 Perennibranchiate Amphibia. He conceived, therefore, that the ana- 

 tomy of these fishes offers a conclusive argument in favour of the 

 theory, long since proposed, that the swimming-bladder of Fishes is 



