‘The proportion of the stuffed specimens of the class Mammalia, exhibited in the glazed cases of the Southern Zoological Gallery and Mammalian Saloon, is in good condition. [Sidenote: THE GROWTH OF THE NATURAL HISTORY COLLECTIONS. 1850–1861.] The stuffed specimens, which, from their bulk, or from want of space in the cases, stand on the floor, have suffered in a certain degree from exposure to the corrosive smoke-dust of the metropolis, the effects of which cannot be wholly prevented.’ The proportion, continues Mr. OWEN, of the Collection of Mammalia consisting of skins preserved in boxes, the Osteological specimens, including the horns and antlers, and the specimens kept in spirit, are all in a good state of preservation. The unstuffed, Osteological and bottled specimens are unexhibited and restricted in use, as at present located, to scientific investigation and comparison; but it is with difficulty that the special visitor for such purposes can now avail himself of these materials, owing to their crowded accumulation in the Basement Rooms in which they are stored. ‘The exhibited Collection of Birds is in a good state of preservation, is conveniently arranged for public inspection, and is usefully and instructively named and labelled. The interest manifested by visitors, and the satisfaction generally expressed in regard to this gallery, indicate the amount of public instruction and gratification which would result from a corresponding serial arrangement and exposition of the other classes of the animal kingdom. ‘The stuffed and exhibited selections from the classes of Reptilia and Fishes, are in a very good state of preservation; they suffer less from the requisite processes of cleaning than the classes covered by hair, fur, or feathers. ‘Of these cold-blooded Vertebrates the proportion preserved in spirits is much greater than in Mammals and Birds, and, consequently, through the present allotment of space, the majority of the singular specific forms of Reptiles and Fishes are excluded from public view. Upwards of two thousand specimens in spirits of these classes have been added in the past year to the previously crowded shelves of the basement store-rooms, where access to any individual specimen is a matter of some difficulty, if not hazard. Of the above additions, fourteen hundred and fifty-six have accrued from the donation of the Secretary of State for India in Council. The interest and novelty of the specimens have constrained their acceptance, and the same reason has led to the acquisition of many additions from other sources. ‘Amongst them deserve to be specified two specimens of that singular snake, the _Herpeton tentaculatum_, known for a century past only by a single discoloured example in the Paris Museum; those now in the stores of the British Museum were acquired from Siam, and have served to enrich Zoology with a complete knowledge of the species, through the descriptions and figures by Dr. GÜNTHER.