146 Trench National Institute. 



With respect to the predisposing causes, ;. e. why some 

 animals are subject to sleep in winter and others not ; and 

 with respect to the preserving causes, i. e. what renders them 

 susceptible of reviving, notwithstanding the suspension of 

 functions which seem most necessary to life, — nothing yet 

 has been advanced which offers a satisfactory solution of 

 these questions. 



M, Geoffrey has presented to the Institute some frag- 

 ments of a great work which he has umlertaken upon Com- 

 parative Osteology. He endeavours to push further than has 

 been hitherto done, the analogies between the corresponding 

 parts of various vertebral animals, — analogies which Aristotle 

 had already recognised, and upon which he founded his 

 works of Natural History. 



M. Latreiile, already known by his great work upon In- 

 sects in fourteen volumes, published as a supplement to 

 Buffon, has added to his other labours a work in Latin, 

 under the title of Genera Inscctorum et Crustaceorum, three 

 volumes of which have already appeared, in which he has 

 classed them with method and precision. 



M. Dumeril, professor of anatomy in the School of Me- 

 ■ dicine, the editor of M. Cuvier's Comparative Anatomy, 

 and author of several valuable works, has presented three 

 Memoirs this year to the Institute. In the first he treats of 

 the mechanism of the respiration of fishes, which is nearly 

 the same with that of deglutition in other animals, but it is 

 effected by more complex organs ; he points out several in- 

 teresting singularities, and among others, the way in which 

 lampreys, rays, and several squali take in water; their 

 mouth being fixed to the stones or the sand, cannot be used 

 for this purpobc, but it is efiected by means of apertures, 

 called vents, made in the upper part of their heads, and fur- 

 nished internally with a valve which admits of water entering 

 when the cavity of the mouth is dilated, but which leaves 

 no other outlet but the gills, when this cavity is shut. 



In his second Memoir, M. Dumeril treats of the senses of 

 smelling and taste in fishes. He thinks their tongue is in- 

 sensible to taste, on account of the dryness and hardness of its 

 integuments, and the continual passage of water over them 

 in respiration ; hut their pituitary membranenot being suscep- 

 tible of<smeil like ourg, since it is not affected by elastic va- 

 pours, niay very probably be the seat of the organ of taste, by 

 transmitting the impression of substances dissolved in water. 



The third Memoir is a coniparative view of the various 

 vital and animal functions, in the order of reptiles called 

 Bairacice, whence it results that the division of this order 



into 



