ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 2T 



Development of Hypophysis in Dogfish. — E. A. Baumgartner 

 {Journ. MorpM., 1915, 26, 301-4-16, 43 figs.). The several parts of 

 the hypophysis in Squalus acanihias are called '' anterior lobe," " inferior 

 lobes," and " superior lobe." Ratke's pouch forms the posterior part of 

 the anterior lobe, the rest being due to a later anterior ectodermic in- 

 vagination. The inferior lobes arise from the sides of Ratke's pouch.. 

 The superior lobe develops from the caudal (superior) end of the hypo- 

 physial primordium. In the course of development the hypophysis 

 shifts about 145°, so that the upper wall becomes the floor and the 

 ventral (anterior) surface the roof. There is glandular growth from 

 roof to floor. The cells of anterior and inferior lobes are acidophilic^ 

 and in general chromophilic. The cell columns of the superior lobe are 

 solid, as Sterzi said. There are spaces with some colloid-like secretion^ 

 which also occurs in the lumiua of the tubules of the anterior and 

 inferior lobes and in the large main lumen. J. A. T. 



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Development of Wolffian Body of Pig.— E. J. Angle {Trails^ 

 Ame/\ Micr. Soc, 1918, 37, 215-38, 7 pis.). The two distal portions 

 of each primary tubule and the Malpighian capsule are derived from th& 

 Wolffian vesicle. It appears that the first portion of the tubule arises 

 as an outgrowth from the Wolffian duct. The secondary canals and 

 glomeruli arise independently of the primary through a process of 

 differentiation of the Wolffian mesoblast. J. A. T. 



Development of Cat's Skull.— R. J. Terry {Journ. MorphoL^ 

 1917, 29, 281-433, 12 pis.). We cannot do more than select a few 

 conclusions from this careful study of the primordial cranium of the 

 cat. The basal plate of the occipital region is derived from a pair of 

 parachordal cartilages, and from two, probably three, hypochordal 

 commissures or arches. The developmental processes in the occipital 

 region are in principle comparable to those of an atypical vertebra of 

 the atlas kind. The basal plate of the occipital region falls into the 

 category of arch structures, not centra. The condyles belong to the 

 part of the basal plate derived from parachordals, and belong to arch 

 structures. The origin of the cartilaginous pars canalicularis of the otie 

 capsule is independent of other parts of the cranium. The pars- 

 cochlearis arises in connexion with the pars canalicularis and the supra- 

 facial commissure. The latter is continuous with the orbito-parietal 

 commissure, and is therefore, in part at least, to be regarded as a parietal 

 structure. The cochlear capsule forms independently of the basal 

 plate, which in the cat is reduced to a narrow bar in the otic region. A 

 pterygoid element appears as a condensation of mesenchyme, in which 

 ossification is occurring at the stage of the 23 • 1 mm.-embryo. Cartilage 

 is subsequently developed, in which ossification proceeds. There is 

 evidence of two ossific centres, and from these the medial pterygoid 

 lamella and hamular process are formed. Jacobson's cartilage in the cat 

 is the anterior, well-developed, portion of a paraseptal cartilage, con- 

 nected posteriorly with the lamina transversalis posterior. J. A. T. 



Influence of Abnormal Temperature on Developing Nervous 

 System of Chick. — Florence M. Alsop {Atiat. Record, 1919, 15^ 

 307-31, 13 figs.). Excessive heat and a limited amount of heat caused 



