137 
varies greatly, some being globular, some slightly flattened, 
others, as the *‘sand-dollars,’’ extremely so. The spines undergo 
strange modifications. 
In the south end of Case 12 are exhibited a portion of the 
Holothuroidea, or sea-cucumbers. Several alcoholic examples of 
these will be found in the Wall-case, 3. 
In Case 12 are also found a few worms and a few species of 
the Polyzoa. Others of both groups are contained in Wall-case 3. 
Overhead in this room is suspended a life-size model of the 
enormous Octopus^ or devil-fish, which occurs on the coast of 
California. 
HALL 23. 
OSTEOLOGY. 
The osteological collection consists of mounted skeletons of 
over 225 species. These belong to more than thirty orders and 
150 families, making it a most valuable means for the study of the 
structure of the Vertebrata. The cases are arranged against the 
walls. In the middle of the hall stand skeletons of the elephant 
and the giraffe. In the alcove of this hall stand skeletons of the 
wapiti, the hippopotamus, the rhinoceros and the camel. 
Case 1 occupies the west side of the hall and a portion of the 
north side. On the north side the series of skeletons begin with 
those of the fishes. These are followed by those of the amphibi- 
ans and reptiles; among which are skeletons of the python, gavial, 
crocodile, turtles and lizards. The middle portion of this case 
contains skeletons of the birds, over fifty in number, among which 
are skeletons of the ostrich, emu and the rhea. The remainder of 
this Case together with Cases 2, 3 and 4, contain skeletons of 
mammals. The arrangement corresponds to that of the mammals 
in rooms 19 and 20, viz, : beginning with the Proiotheria and end- 
ing with the Quadrumana. The remainder of Case i is occu- 
pied by skeletons of mammals. These are continued into Case 2, 
which contain skeletons of goats, prong-horn and llama. 
Case 4. — Contains the remainder of the mammals, ending 
at the north end of this hall with seventeen skeletons of monkeys 
and lemurs. 
