ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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develop somewhat late, distally to tho ostium, but at a considerablo 
distance proximally from the end of the bulbus ; the proximal end of 
the bulbus is involved in the formation of the ventricle ; the distal end 
divides into the three arterial stems ; the pads ( Wulste) of the bulbus 
are histological marks of its cardiac nature, and these are lost as such 
in the distal portion, while their modification is expressed histologically 
in the peripheral vessels ; the arterial valves of Amniota do not arise at 
the ostium bulbi, but correspond to the distal valves of Amphibians. 
Development of Abdominal Vein in Amphibia.* * * § — Prof. F. Hoch- 
stetter has studied this in Salamandra maculata, and comes to the pro- 
bable conclusion that the rudiment of the abdominal vein in Amphibia 
is the foundation for the development of the umbilical veins of Amniota. 
Its cranial portion, which has only a transitory role in Amphibia, is 
directly modified into the corresponding portion of the umbilical vein, 
while its caudal portion exhibits in many Reptiles the same relations as 
in Amphibia, but is undeveloped in Birds and Mammals. 
Development of Hypophysis and Saccus vasculosus in Teleostei 
and Amphibia.j — Herr H. Lundborg has had for investigation embryos 
of Saimo salar , S. alpinus , the Axolotl, and the Triton. He finds that, 
in the Salmonidse, the hypophysis is an ectodermal structure ; though 
the ectoderm in its neighbourhood consists of two layers of cells, it is 
the deeper one that takes part in forming the hypophysis. From the 
first the hypophysis is double, though the two ectodermal invaginations 
lie close to one another; the partition between them thins after some 
time, and then breaks first in the middle, and afterwards before and 
behind. A hypophysial duct (or, more correctly, stalk) appears, but it 
is very short, solid, and vertical in direction. As soon as the embryos 
are set free the duct disappears. 
At the stage when the Saimo is about to escape there is developed 
on both the upper and the lower jaw a dermal fold, which bounds the 
mouth-opening. These folds are secondary structures, and as the teeth 
are developed on them they are not, as Dohrn supposed, endodermal, 
but ectodermal structures. 
The glandula infundibuli does not begin to be separated off from the 
infundibulum till a comparatively late period (in S. salar the 65th day) ; 
in the Axolotl it appears still later ; there is always a vertical orifice of 
communication between the infundibulum and the rudiment of the organ. 
Development of Olfactory Organ in Teleostei.^ — Herr J. F. Holm 
gives a brief account of the development of this organ in Saimo salar , 
from which it appears that the process more closely resembles that of 
Elasmobranch Fishes than of Lepidosteus , as described by the late F. M. 
Balfour, who with C. K. Hoffmann seems alone to have studied the 
history of this organ in Fish. 
Ova and Larvae of British Fishes.§ — Prof. W. C. MTntosh com- 
municates the results of his studies at St. Andrews on Hippoglossus 
* Morph ol. Jahrb., xxi. (1894) pp. 19-27 (1 pi.), 
t Zool. Jahrb. (Abth. f. Anat.), vii. (1894) pp. '667-87 (2 pis., 4 figs.), 
t Morph. Jahrb., xxi. (1894) pp. 620-4 (1 pi., 1 fig.). 
§ Ann. and Mag. Nat. Hist., xiv. (1894) pp. 189-95. 
