Febbuaey 13, 1903.] 



SCIENCE. 



253 



The Eyes of a Specimen of the Cuian 

 Blind Fish, Lucifuga, and those of Her 

 Four Young (with lantern slide illustra- 

 tions) : C. H. EiGENMANN, Indiana Uni- 

 versity. 



Faunal Characteristics of the Sandusky 

 Region: Herbert Osborn, Ohio State 

 University, Columbus, Ohio. 

 The Sanduslry region as here defined 

 includes parts of Erie, Sandusky and Ot- 

 tawa counties, Ohio. Practically all the 

 faimal elements of the region are to be 

 found within five miles of the city of San- 

 dusky. A brief summary of faunse rep- 

 resented and the faunal conditions afforded 

 is given, with illustrations in different 

 groups. The region includes a lowland 

 and partially timbered area of rather rich 

 vegetation and diverse fauna; a beach and 

 sand-dune fauna; a swamp and marsh 

 fauna; a fauna pertaining to rocky coast 

 and island, and one peculiar to a prairie 

 area, approaching plains conditions in 

 scant flora; aquatic faunre pertaining to 

 bay, coves, river and lake, with abimdant 

 plankton, nekton and littoral elements. 



Protoplasmic Old Age: Gary N. Calkins, 

 Columbia University, New York city. 

 The 'A series' of Paramcecium experi- 

 ments died out December 19, 1902, in the 

 742d generation. The last few individ- 

 uals were perfectly normal so far as size, 

 feeding, etc., were concerned. The history 

 of the series tends to the conclusion that 

 there is a definite potential of dividing 

 energy which is possibly connected with a 

 definite substance of the cell— archoplasm 

 or kinoplasm. 



The Structure, Development and Function 

 of the Torus longitudinalis of the Tele- 

 ost Brain: Porter Edward Sargent, 

 Cambridge, Mass. 



Morphology. — The torus longitudinalis, 

 as typically developed, consists of a pair 

 of longitudinal ridges or pads projecting 



downwaixl from the thin median portion 

 of the mesencephalic roof and extending 

 from the posterior commissure through 

 the length of the mesencephalon. The 

 form and relative size of the torus, and 

 consequently its relations to the surround- 

 ing structures, vary greatly in the hundred 

 or more species -examined. 



Ontogeny.— The torus longitudinalis is 

 developed from the roof of the mesen- 

 cephalon as a longitudinal thickening of 

 its median portion. More exactly, each 

 lateral lobe of the torus is differentiated 

 from the mesal edge of the tectum of the 

 corresponding side, the precise mode dif- 

 fering somewhat in the different groups 

 of teleosts. 



Finer Anatomy. — Each lobe of the torus 

 has a framewort of radiating ependymal 

 fibers. The nerve cells are of relatively 

 small size, and frequently are arranged in 

 parallel rows between the ependymal 

 fibers. The cells are usually bipolar, but 

 ultimately give rise to three sets of neu- 

 rites. The first forms the tractus toro- 

 tectalis, which runs into the tectum and 

 ends in the superficial fiber zone in con- 

 tact with the retinal fibers of the optic 

 nerve. Another set of fibers passing out 

 of the torus with the preceding forms the 

 tractus toro-cerebellaris, which courses 

 obliquely around the lateral border of the 

 optic lobe and enters the cerebellum. The 

 third set of neurites forms the tractus toro- 

 fibrse Reissneris, which enters the ventricle 

 in separate fascicles, there becoming united 

 to form the compact fiber tract known as 

 Reissner's fiber. 



Function. — The cells of the torus are, 

 then, in connection by their afferent neu- 

 rites with the endings of the optic nerve, 

 and by their efferent neurites with the 

 body musculature through Reissner's fiber. 

 It is evident, therefore, that the torus 

 longitudinalis is the nerve center for the 

 receipt of those impulses coming in over 



