14 FREDERICK TILNEY AND LUTHER F. WARREN 



pineal body in the mouse resembles the pituitary body in reptiles 

 with certain small differences. Meynert (77) 271 expresses the 

 opinion that the parallelism between the pineal body and the 

 pituitary body is a mistaken idea. He believes that the epi- 

 physis should be considered a ganglionic derivative of the teg- 

 mentum. It contains two types of cells, namely, those with a 

 diameter of 15 micra and those with a diameter of 6 micra. The 

 pineal body, in Meynert's opinion, differs from other ganglia 

 only in the fact that the cells are very close together. Krause 

 (76) 218 observed in the pineal body nerve fibers having a double 

 contour. Henle (71) m described the parenchyma of the pineal 

 body as subdivided by fibrous processes called septa such as 

 occur in lymph glands. These divisions gave rise to more or 

 less independent follicles or acini varying in size from 6 micra to 

 30 micra in diameter. It was Henle's opinion that the pineal 

 body resembles more exactly lymph glands than any other 

 tissue in the body. Stieda ('65) 375 in several species of amphibia 

 observed an epithelial structure between the eyes in the frontal 

 region of the head which he called the frontal cutaneous gland. 

 Subsequent investigation revealed that this so-called cutaneous 

 gland was in fact a portion of the epiphyseal complex. Paw- 

 lowsky (74) 308 described fibers in the epiphysis which seemed to 

 be derived from the posterior commissure. Huxley (76) 191 

 described the pineal body in Ceratodus forsteri. In this form 

 it occurs as a slender, cylindrical body. Baudelot (70) u gave 

 a detailed description of the pineal body in Gadus merlangus. 

 He also found it in the salmon and in the Cyprinoids. Camper, 55 

 although he observed it in many fish, was not able to find it in 

 haddock or cod. Arsaky 8 was unable to detect the pouch of 

 the pineal body in fish. Haller (1768) 165 did not observe the 

 pineal body in birds nor did he observe it in the pike or trout. 

 He did find it, however, in the carp and tench. 



Owen's ('81 ) 293 view of the conariohypophyseal organs is such 

 that it at least deserves comment, if only as a historical curiosity. 

 According to Owen, the central nervous system in annelids forms 

 a ring through which passes the oesophagus (cesophageal ring). 

 In higher vertebrates, especially in embryonic life, the nervous 



