

1892.] Dr. A. HiJl. The Hippocampus. 5 



be formidable antagonists to the smaller land Vertebrates of the 

 period. 



The report of Dr. Scudder will complete the account of the land 

 animals of the erect Sigillariee of the South Joggins, unless by new 

 falls of the cliff fresh trees should be exposed. From 1851, when the 

 first remains were obtained from these singular repositories by the 

 late Sir Charles Lyell and the writer, up to the present time, they 

 have afforded the remains of twelve species of Amphibians, three 

 land Snails, eight Millipedes, three Scorpions, and an Insect. 



The type specimens of these animals have been placed in the Peter 

 Redpath Museum of McGill University, and such duplicates as are 

 available will be sent to the British Museum and that of the 

 Geological Survey of Canada. 



III. " The Hippocampus." By ALEX HILL, M.D., Master of 

 Downing College. Communicated by Prof. A. MACALISTER, 

 M.D., F.R.S. Received May 4, 1892. 



(Abstract.) 



The subject of this paper is the hippocampal region of the brain in 

 anosmatic animals. Several specimens of the brain of the bottle- 

 nosed, whale, narwhal, porpoise, and calf-seal were obtained for the 

 purpose of studying the extent to which the hippocampus in animals 

 totally destitute of the sense of smell, or possessing it in a very small 

 degree, departs from the ordinary type. 



The hippocampal region was, in each case, cut into a series of 



ectiohs, which showed that there is, in the brains of Hyperoodon 



and Monodon, no fascia dentata; in Phocoena this formation is very 



rudimentary ; in Phoca it is rather less strongly developed than in 



man. 



As a standard of comparison, the hippocampus of the ox was 

 studied in a similar manner. Certain points which have not been 

 described hitherto with regard to the anatomy and histology of the 

 hippocampus in macrosmatic brains are noticed. Other peculiarities 

 in the general form and in minute structure which distinguish 

 the brains of anosmatic animals are also mentioned incidentally. 



The discovery that the fascia dentata is completely absent in 

 animals which possess no olfactory bulb or tract, and that it varies 

 in development directly as the size of these organs, throws light upon 

 the function of the hippocampal region, and seems to call for a fresh 

 definition of its several parts and a revision of the nomenclature of 

 the region. The paper contains an historical survey of the ter- 

 minology and suggestions for its revision. 



