370 DENDRITIC APPENDAGE OP UROGENITAL PAPILLA 



the thicker parts. In fact, the characteristic colour of the organ is 

 caused by these blood-vessels and capillaries. 



The dendritic appendage is found equally developed in the 

 two sexes as was, according to Brock, ascertained by Kner in 

 1855 ; in fact the sex can be determined only by an examination of 

 the generative organ. The appendage is also found" from the very 

 earliest stages of growth being simpler in structure, the earlier the 

 stage. For instance. Fig. 9 represents somewhat enlarged the organ 

 belonging to the very young individual shown in Fig. 8 in its natural 

 size. It is already divided into two more or less symmetrical halves 

 but each half consists only of a few lobes marked with shallow pits. 

 It is at this stage coloured not only by blood but like the body proper 

 by fine dots of black pigment which becomes dispersed and almost 

 invisible in the adult. 



In passing, I may remark that Brock's Figs. 1 and 2 appear to 

 me somewhat unfortunate as representations of nature. His Fig. 1 

 almost makes me think that the species he observed is different from 

 mine, ^^ but the difference probably arises from the unsatisfactory state 

 of his preserved specimens. 



Internal Structure. 



When we cut the organ in cpiestion into serial sections, we 

 soon observe that it is built up of two concentric zones, of which 

 the outer or the cortex consists of îi parenchyma-like epidermis 

 containing also slime cells and well developed glandular cells, 

 while the inner zone or the cerium consists of smooth muscular 



1) For specific identification, I have mainly relied on Giinther's Cat. of the Fishes in the 

 Brit. Museum, but have also referred to Desmarests' Hist. Nat. de Lacepède and to Schlegel's 

 Fauna Japonica, Poiss. 



