1885.] Embryology. III5 
(Jour. Anat. and Phys., January, 1881) gives the result of an 
examination of the bones, articulations and muscles of the 
rudimentary hind-limb of the Greenland right whale. Ten sets 
of these parts were dissected. The synovial capsule of the 
knee-joint, the acetabular cartilage, a synovial cavity and head 
of the femur are present, and an apparatus of strong ligaments 
is attached to the femur, permitting and restraining move- 
ments in certain directions. But these movements of the fe- 
mur are limited, and in two examples the hip-joint was anchy- 
losed without trace of disease. The muscles of these bones may 
be arranged in four groups, three of which connect them with 
other parts: (1) Internally with the genital organs; (2) a poste- 
rior or caudal mass; (3) an anterior or trunk mass; while the 
fourth connects the bones to each other. According to Mr. 
P. L. Sclater, the wild ass of Somaliland is a new species, or at 
least subspecies, and is distinguished from that of the Nubian 
desert by its generally paler and more grayish color, the entire 
absence of the cross stripe over the shoulders, the very slight 
indication of the dorsal line, and the numerous black markings 
on both front and hind legs. It has also smaller ears and a 
larger and more flowing mane. Mr. W. Leche (Proc. Zool. 
Soc., 1884) describes some Chiroptera from Australia, including 
the new species Wyctinomus petersi and N. albidus. In the latter 
Species the ears are much larger than the head, and are united by 
a low band. Mr. J. W. Clark describes (in the Proc. Zool. Soc.) 
a series of stuffed sea-lions belonging to the Australian Museum, 
Sydney, and from a study of these and other examples concludes 
that Otaria cinerea is “ one of the four distinct species of Otaria 
inhabiting the Australian coast.” M. Fernand Lataste contrib- 
utes to the Proc. Zool. Soc. for 1884, a description of a new 
Species of Meriones, M. longifrons, from Arabia, together with a 
full account of its habits, intelligence and sexual relations. 
Gestation normally lasts twenty days, and the ovarian period about 
ten days. 
EMBRYOLOGY.’ 
Tue ArcuistomE-THrory.—The new doctrine of development, 
of which it is proposed to give a brief and partial sketch here, rests 
in part on a hypothetical basis and in part upon a well established 
theory founded upon observation. It consists further in an expan- 
sion and adaptation of the gastreal-theory of Haeckel in the light 
of more recent research, and a reconciliation of it with the deduc- 
tions of His, Rauber, Whitman and myself, as to the occurrence 
of concresence of the lips of the blastophore and the differentia- 
tion of the axis of the body of the embryo from behind forwards, 
generally of bilateral types with paired mesoblastic sacks derived 
Edited by JoHN A. RYDER, Smithsonian Institution, Washington, D. C. 
