248 



CLAP p. 



[Vol. XV. 



Cut 8. — Cross-section of strand between organs 

 9 and 10 of infraorbital line of Batrachus. 



often near the organ a suggestion of a lumen is noticed, 

 especially in longitudinal sections. 



According to Leydig (i), Fee (27) seems to have figured this 

 connecting strand, but makes no allusion to it. Solger (25) 

 refers to the "side organ chains," in the case of Acerina cer- 

 nua and Lota vulgaris, and speaks of the chain as consisting 

 of "marrowless nerve fibres enclosed in a nucleated sheath." 

 Merkel (20) speaks of " modi- 

 fied (cutis) epithelium " and 

 suggests that the connecting 

 strand may be the vestige 

 of a canal ! The presence, 

 however, of both the canal 

 and the connecting strand, 

 one found within the other, 

 as in Batrachus, would over- 

 throw any such supposition. 

 Carriere (28) thinks there is no possibility that this "chain " is 

 composed of nerve fibres. Ryder (29) speaks of "faint fila- 

 mentous prolongations " from the organs. In a figure of 

 Savi's (40) vesicles there is a connecting cord shown and 

 described as " filament anastomotique," which suggests the 

 same structure. 



Leydig (i) has examined this peculiar structure in Gobio, 

 Rhodeus, Salmo, and Anguilla, and although reaching no con- 

 clusion as to its significance, says that the strand does not 

 consist of nerve elements, but principally of epithelial cells 

 which enclose a space that may be considered a lymph passage, 

 or, in some cases, no lumen being present, the strand presents a 

 fibrous or ligamentous appearance. He regards the " epithelial 

 canals" of Fierasfer as lymph channels. Leydig (i) further 

 observes that although he has not seen the epithelial thick- 

 enings out of which the sense hillocks arise, it is probable that 

 the strand is derived from these thickenings. From this point 

 of view the strand would be a remnant of an epithelial growth 

 which separates from the epidermis and forms the foundation of 

 the sense hillocks. Leydig (i) utterly discards the idea that this 

 structure is in any way connected with the later forming canal. 



