ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 605 



blood becomes charged with fatty material which is conveyed to the 

 ovary for the formation of yolk, and that the excess of this fatty material 

 is deposited in the comb, and probably in other situations as well. 



The author calls attention to the close parallel between. the fat 

 metabolism of the laying hen and that in spider-crabs parasitized by 

 Sacculina. 



Development of Turtle Skull.*— B. W. Kunkel gives an account of 

 the development of the skull in Emys lutaria. The most general result, 

 is to show its far-reaching resemblance with that of Lacerta, in spite of 

 the great differences in the adult result. 



Sympathetic Nervous System in Turtles. f — A. Kuntz has made a 

 series of observations on the development of the sympathetic nervous 

 system in turtles, in continuation of his investigation into the develop- 

 ment of the sympathetic nervous system of Vertebrates. In embryos of 

 turtles the " Anlagen " of the sympathetic trunks arise as cell aggregates 

 lying along the lateral surface of the aorta and along the dorsal surface 

 •of the carotid arteries. The cells which give rise to the rudiments of 

 the sympathetic trunks have their origin in («) the spinal ganglia, or in 

 the neural crest, and (b) in the neural tube. Before the spinal nerves 

 can be traced peripherally, cells advance from the distal ends of the 

 spinal ganglia directly through the mesenchyme into the rudiments of 

 the sympathetic trunks. After the spinal nerves have grown peripherally, 

 cells migrate from the spinal ganglia, and from the ventral part of the 

 neural tube along the paths of the spinal nerves and of the communi- 

 cating rami into the rudiments of the sympathetic trunks. About the 

 eleventh day of incubation the cell-aggregates begin to break up and 

 become scattered for a considerable time, after which the cell-groups 

 again become aggregated into compact ganglia. About the thirteenth 

 day of incubation cell-strands push out from the spinal nerves proximal 

 to the origin of the communicating rami, and advance towards the aorta. 

 These cell-strands increase in size and advance mesially until, at the 

 close of the sixteenth day, they appear as irregular cellular tracts extend- 

 ing from the spinal nerves into the rudiments of the sympathetic trunks. 

 A comparative study of the development of the sympathetic trunks in 

 embryos of the turtle and of the chick strongly suggests a more or less 

 direct phylogenetic relationship between the sympathetic nervous system 

 in Birds and in the ancestral type of Reptiles. The prevertebral plexuses 

 arise as cell-aggregates lying along the ventro-lateral aspects of the aorta. 

 They are derived from cells which migrate ventrally from the rudiments 

 of the sympathetic trunks. In the sacral region cells may be traced 

 ventrally from the rudiments of the pre-vertebral plexuses into the 

 sentery, where they become aggregated into small cell-groups associated 

 with the rectum. These sympathetic cell-groups probably represent the 

 meprototype of the ganglion of Remak in birds. In the region of the 

 genital ridges cells migrate ventrally from the •"Anlagen" of the pre- 

 vertebral plexuses and become aggregated into small cell-groups asso- 

 ciated with the rectum. The vagal sympathetic plexuses in the walls of 



* Auat. Anzeig., xxsix. (1911) pp. 354-64 (3 figs.), 

 t Amer. Journ. Anat., ii. (1911) pp. 297-312. 



Oct. ISth, 1911 -2 i; 



