514 DEVELOPMENT OF THE SIMPLE TISSUES, BY S. STEICKER. 



the cleavage cavity to the roof, and which, after the forma- 

 tion of the semilunar fissure, remain adherent to the roof, are 

 continuous with those cells which were above described as be- 

 longing to the internal thicker layer of the inferior segment of 

 the back. In other words, that which subsequently adheres to 

 the roof of the cleavage cavity is the rudiment of the motor 

 and intestinal gland laminae. 



I have already mentioned that in the original roof of the 

 cleavage cavity only the analogue of the sensorial lamina of 

 Remak is to be looked for. This lamina, however, as I* and 



Fig. 401. 



Fig. 401. The illustration here reproduced was obtained from a 

 remarkably successful preparation made in the year 1860. How far 

 it is diagrammatic in its finer details I am unable to say, but the main 

 features are undoubtedly as correct as possible. I have therefore no 

 hesitation in giving it here, notwithstanding that the same relations 

 have been excellently illustrated by Gotte, v. Bambeke, and Golubew. 

 My figure appears to me to materially facilitate the understanding 

 of the parts in question, and it is on this account that 1 give it. The 

 letters D, F, P, Z, z, as in fig. 400 ; a, dorsum of the embryo ; s, 

 septum between the food cavity, N t and the cleavage cavity. 



v. Bambekef have shown, is composed of two layers in the 

 Batrachia, of a superficial layer of brown cells forming one tier, 

 and of a deeper layer of whitish cells, which in some parts 

 form a single tier, and in others, many tiers. The external 

 brown cells constitute the rudiments of the horny or corneal 



* Loc. cit. 



t Recherclies sur la developpement du Pelobates brun, Memoire publie par 

 V Academic Belgique, Tom. xxxiv. 



