456 Bibliographical Notices. 



mammalian affinities of the Stonesfield remains, of the Pterodactyles 

 of the chalk, or the Birds' bones of the Wealden strata, will feel the 

 force of the above remark. And now, when every year bids fair to 

 unveil to us new, or hitherto unlooked-for, forms amidst the earher, 

 or even earhest, scenes of the earth's physical history ; and the old 

 coast-line or ancient estuary yields traces of footsteps belonging to 

 some unknown beast, perhaps seeking shelter from the storm (its 

 impress still remaining), or tracing its way on the rippled sands left 

 moist by the receding tide— footsteps so numerous as to lead us to 

 infer some corresponding solid skeleton ; a fragment of bone might 

 guide us along the path of discovery, as to its nature. 



Prof. Quekett has, as is well known, been already engaged on 

 some of these points of original investigation. In inquiries of such- 

 like character, this volume would be an indispensable requisite, con- 

 taining as it does a description of 945 preparations, of which 385 

 belong to the skeleton of Fishes, 103 to that of Reptiles, 60 to that of 

 Birds, and the remaining 397 to that of Mammaha. Of the most 

 important and striking specimens of these preparations, 432 have 

 been selected for representation, all of which, with but two excep- 

 tions, were drawn by means of the camera lucida. And with a view 

 of rendering the work more useful to the student, in comparing the 

 minute structure of the bones of the four great classes of animals, 

 the greater part of the sections have been drawn under two powers, 

 one of 95, the other of 440 diameters, it having been ascertained that 

 the size and arrangement of the lacunae are frequently of the greatest 

 importance in determining the true nature of fragments of recent and 

 fossil bone, when other characters are wanting. The numerous pre- 

 parations above noticed consist of sections of the tissue of the endo-, 

 exo-, and splanchno-skeletons of Fishes ; the endo- and splanchno- 

 skeletons of Birds ; and the endo-skeleton of Reptiles and Mammals ; 

 the term splanchno or visceral skeleton being applied to the hard 

 bony tissue found in certain viscera and organs of sense, as in the 

 heart of the Hog and most old Ruminants, and the eyes of Fishes and 

 Birds. A short introduction is given, in which the principal structures 

 of bone are enumerated and described, as the Haversian canals and in- 

 terspaces, the laminae, lacunae, canaliculi, &c. The body of the work 

 is chiefly occupied by elaborate descriptions of the figures ; a few 

 notes, however, explanatory of the principal points of interest, pre- 

 cede each division. 



In describing the bone of Mammalia the minute structure is stated 

 to be nearly uniform throughout the whole class, each Haversian 

 system being surrounded by a series of concentric laminae with 

 lacunae placed between them, and giving off numerous canaliculi in 

 a radiating manner. It is a remarkable fact, however, that those 

 Mammalia which resemble Birds in their habits or internal ana- 

 tomy, approach most nearly to these animals in the minute structure 

 of their bones ; such is the case in the Ornithorhynchus, Echidna, 

 Sloth, Kangaroo and Bat. 



Copious details are given of that singular animal, the Lepidosiren, 

 forming the connecting link between Fishes and Reptiles. Fourteen 



