32 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Passer in regard to tlie origin of the sympathetic nervous system. He 
has no doubt that the sympathetic ganglia arise from the spinal ganglia 
and therefore from the ectoderm. A proliferation in a ventral direction 
from the ganglionic rudiment gives rise to elements which gradually 
accumulate dorsally, and approach the walls of the aorta and cardinal 
veins. They are at first scattered in the mesenchyme, but come to form 
a cord in which the spinal ganglia arise dorsally and the sympathetic 
ventrally. 
Bulbus Cordis in Birds and Mammals.* * * § — Dr. A. Danger finds that 
in Birds the division in the bulbus proper is effected by the fusion of 
longitudinal pads, which correspond to the bulbus-pads in Reptiles. At 
the origin of the bulbus, however, the division is effected by a fusion 
of two pads which probably correspond to the ostium-pads of Reptiles. 
The valves, as in Reptiles, take their origin wholly from the bulbus- 
pads. In the Mammalian embryo the two ostium-pads, and the first and 
third bulbus-pads have fused into two longitudinal pads. For details, 
however, which are difficult to state without the accompanying figures, 
the original paper must be consulted. 
Development of Wing of Sterna Wilsoni.t — Mr. Y. L. Leighton 
finds that, in Wilson’s Tern, there are at least seven elements in the 
carpus, and four distinct metacarpals. The evidence is in favour of the 
persistent digits of the bird’s wing being II., III., and IV., and not I., 
II., and III. 
Notes on Development of Amphibia.f — Dr. H. H. Field finds that 
the arcliinephric capsule of Amphibians is a product of the protovertebra ; 
an analogous organ is, in all probability, present in Acipenser sturio and 
in Petromyzon. It is not, however, an independent organ, but represents 
the last remains of a protovertebral process, the ventrally growing edge 
of which gives rise to muscles. The ventral musculature arises, along 
the whole length of the body, from this part of the protovertebra. The 
elements which are destined for the musculature of the extremities are 
at a very early stage likewise given off from the ventral part of the 
protovertebral process. 
The connective tissue elements of the limbs arise from a thickening 
of the lateral somatopleure which combines with the elements derived 
from the protovertebra to form an apparently homogeneous “ Anlage.” 
In Amblystoma a very small number (about three) of the protovertebras 
take part in forming the “ Anlage ” of the anterior extremity. The 
presence of a serially homologous somatopleuric thickening between the 
two pairs of limbs may be taken as an indication of the previous existence 
of a continuous fold. 
Origin of Bones of Teleosteans.§ — Mr. R. G. Harrison doubts the 
correctness of Dr. H. Klaatsch’s conclusion that the scleroblastic cells of 
Vertebrates are derived exclusively from the ectoderm. He brings for- 
ward evidence to show that the apparent disappearance of the membrane 
bones at certain points, and the incrowding of ectodermal cells into the 
* Morph. Jahrb., xxii. (1894) pp. 99-112 (11 figs.). 
t Tufts College Studies, No. 3 (1894) pp. 03-76 (1 pi. and 7 figs.). 
% Anat. Anzeig.. ix. (1894) pp. 713-23 (5 figs.). 
§ Op. cit., x. (1894) pp. 138-43 (3 figs.). 
