August 24, 1900.] 



SCIENCE. 



309 



fish 60 mm. long which measured 3.8 mm. 

 from cornea to optic nerve and. 4.7 mm. 

 longitudinally with the eye of a fish 335 

 mm. long measuring 10 and 13 mm. respec- 

 tively along the lines measured in the 

 smaller specimen shows (1) that no new 

 elements are added during the growth of the 

 eye ; (2) the distance between the elements 

 increases about in proportion to the in- 

 crease in the surface of the eye. The ratio 

 between the surfaces of the smaller and 

 larger eye is about 1: 0.144, the average ratio 

 between the distance from center to center 

 of two elements of the pattern in the small 

 and large eye is 1: 0.164 ; (3) on the average 

 the ratio between the size of the elements in 

 the small eye and large eye is 1:2. 



CONCLUSIONS. 



I. The pattern varies in shape from a 

 square on the anterior and posterior edges 

 of the eye to a rhombus on all other parts 

 of the eye except where rows of cones have 

 been interpolated ; and it is largest at the 

 middle of the anterior and posterior faces 

 of the eye. 



II. The cones are arranged in rows 

 which correspond to circles formed on the 

 surface of the eye by two sets of parallel 

 planes. One set of these planes is perpen- 

 dicular to an axis passing from the upper 

 edge of cornea through the center of the eye 

 to the back and the other set of planes is 

 perpendicular to an axis passing in a similar 

 manner from the lower edge of the cornea. 



III. As the surface of the eye increases 

 in size toward old age the area of the pat- 

 terns increases in about the same propor- 

 tion. No new elements are added. 



Development of the Lungs in the Frogs, Rana 

 Gatesbiana, R. silvatica, and R. vireseens : 

 By Marguerite Hempstead, Meadville, 

 Pa. 

 The principal features of the development 



of the lungs in the American frogs studied 



may be stated as follows : 



1. The formation of the respiratory ap- 

 paratus is similar to that in the toad, but 

 differs from the latter in having the com- 

 munication with the pharynx formed very 

 early in larval life instead of at the end as 

 in the toad. 



2. The respiratory apparatus arises as a 

 solid downgrowth from a solid portion of 

 the pharynx, which is unlike the formation 

 of the lungs in Bombinator as described by 

 Goette, and unlike the description of the 

 process in other European forms in all the 

 accounts available for reference. 



3. The lung rudiment is single and solid, 

 and not a pair of hollow evaginations as 

 described by Marshall. 



Development of the Lungs in the Common Toad 

 Bufo lentiginosus and in the Tree Toads 

 {Hyla pickeringii and Hyla versicolor) : By 

 Simon Henry Gage, Cornell University. 

 With the tree toads the pharynx becomes 

 hollow before the external gills are ab- 

 sorbed, and the lungs become hollow and 

 open into the pharynx before the external 

 gills disappear. 



In Bifo the lungs and pharynx very early 

 become hollow, but the larynx remains 

 solid and has no communication with the 

 pharynx until the tail is almost wholly ab- 

 sorbed and the young toad is almost com- 

 pletely transformed. The connection of 

 the lungs with the pharynx seems to be one 

 of the last acts of metamorphosis. When 

 the larynx opens into the pharynx it is 

 lined with ciliated epithelium, apparently 

 the epithelium is non-ciliated before the 

 opening is established. 



In the ciliatiou of the oral cavity and the 

 pharynx of the toad {Bufo) the columnar 

 ciliated epithelium spreads from the oesoph- 

 agus into the pharynx and the mouth. 



Tlie Chronological Distribution of the Elasmo- 

 branchs: By O. P. Hay, American Mu- 

 seum Nat. History, New York City. 

 There is first presented a diagram which 



