ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 455 



of mesoderm which gives no indication of the internal configuration of 

 the endodermic lining. The authors give an account of this exceedingly 

 complex internal configuration and of the stages in its development. 



Pulmonary Circulation in Chick.* — Theodore L. Squier finds that 

 the pulmonary circuit is complete, though not necessarily in its definitive 

 form, in the 72-hour chick. Blood must flow through the pulmonary 

 system at a very early stage, although owing to the relative resist- 

 ances in this and the general systemic circulation the amount passing 

 through the lungs is undoubtedly small. With the general enlargement 

 of the pulmonary system, and finally upon the collapse of the last 

 aortic arch, a circuit adequate for respiratory purposes is not only at 

 hand, but is automatically put in use. The pulmonary vein may be 

 simply a specially developed part of an indifferent plexus present from 

 the beginning in the region from which the lungs grow, the sole 

 survivor of numerous primitive vessels that drain the region surrounding 

 the lung primordium. Or it may be that a median dorsal outgrowth 

 from the sinus wall connects secondarily with the lung capillaries. 



Development of Liver and Pancreas in Amblystoma.f— E. A. 

 Baumgartner finds that the liver in this xlmphibian begins as a median 

 ventral projection of the lumen of the gut, then as an anterior out- 

 pouching from this lumen. There is a later shifting of the posterior 

 part of the liver to the right and dorsally, due to crowding of the 

 stomach and development of the duodenum on the left. A later growth 

 on the left side results in an adult organ with right and left parts, the 

 right side always remaining more dorsal on the lateral side of the 

 stomach. 



The ductus choledochus develops as the early anteriorly directed 

 lumen from the gut. The right and left hepatic ducts develop as 

 divisions of the ductus choledochus, and by division and growth form 

 the hepatic rami and branches. The gall-bladder begins as a median 

 ventral outpouching of the posterior part of the liver-prim ordium. 



The ventral pancreatic primordia are ventro-lateral evaginations of 

 the gut caudal to the cystic primordium. The dorsal pancreatic pri- 

 mordium is a single median dorsal evagination. The ventral pancreatic 

 ducts are constrictions of the two ventral pancreatic primordia ; they 

 afterwards unite in one. The dorsal duct remains a single stem with 

 short lateral branches. 



Life-history of Gurnard. + — Alexander Meek has made a study of 

 Trigla gurnardiis, with special reference to the migrations. He uses 

 the word denatant for migrations with the current, and contrmiatant for 

 migrations against the current. To begin with, there is a denatant 

 drift of eggs and larval stages lasting for a number of weeks, a 



* Anat. Record, s. (1916) pp. 425-38 (2 pis. and 3 figs.). 



t Amer. Journ. Auat., xix. (1916) pp. 211-75 (4 pis.). 



5 Rep. Dove Mar. Lab., Cullercoats, 1915, pp. 9-15 (6 figs.). 



2 I 2 



