THE DEVELOPMENT OF THE TADPOLE. 209 



lines formed by the solar spectra viewed with the greatest obliquity 

 attainable ; the elliptic lines representing a focal plane cutting 

 both sides of the cone of converging rays. 



The central drawing was taken from a huge Indian Moth, 

 Fig. III., crowded with minute beading i — 90,000th of an inch in 

 diameter. 



(To be continued.) 



^be S)c\)elopment of tbe C^a&pole, 



By J. W. Gatehouse, F.I.C. 



Part VIII. Plates XXL, XXII. 



A S the readers of this Journal will probably have discovered 

 fx. for themselves long ere this, the writer of this series of 

 papers can by no means be termed a master of the subject, 

 but must be considered rather in the light of a student trying to 

 observe for himself, and drawing conclusions from these observa- 

 tions made on original sections cut direct from the object 

 studied. Under these circumstances it would be wonderful if he 

 did not fall into mistakes, and if his unknown friends would 

 kindly point out any they may have observed, it would be doing 

 him a real service, as these studies are undertaken as a recreation 

 and change of work from his usual labour. 



One such mistake certainly was made in the last article. 

 An observed structure situate over the front of the fourth 

 ventricle, and connected apparently with the branching processes, 

 which ultimately become the chloroid plexus, was termed the 

 pineal gland. A litde thought would have prevented this 

 structure, of which the writer can find no account in any descrip- 

 tion of the amphibian brain at his command, from being called 

 the pineal gland, as that organ is situate much anterior to the 

 observed position of the one partly described, being in fact at the 

 base of the cerebral lobes, and well in front of the optic lobes, 

 instead of behind them. If any one could kindly give him 



