382 SEA-SIDE STUDIES. 



dig's work on Comparative Histology, the latest authoritative 

 publication. There, indeed, I found the existence of granular 

 nerves stated as a fact, though without specific information 

 either respecting their discoverer or the animals in which 

 they existed ; and without a hint of any physiological signi- 

 ficance in the fact.* On my return home I made diligent 

 search, and by means of Canstatt's Jahresherichte for 1854 

 (p. 66), learned that Meissner had discovered gi-anular trunks 

 in the thread-like tiny worm Mermis ; and H. Miiller and 

 Gegenbaur in the naked gasteropod PhylUrhoe. 



On procuring the memoirs referred to,^- 1 found the fullest 

 confirmation of my own observations, but no appreciation of 

 their physiological significance. Miiller and Gegenbaur say: 

 " Distinct fibres are not discoverable in the trunks, which 

 appear to consist of nothing but a clear granular streaky 

 substance (aus einer hellenfeinkdrnig streijigen Suhstanz). 

 In some instances there were small groups of ganglionic 

 cells." And this is all they remark. 



Meissner's observations are given in gi-eater detail, and 

 appear to have suggested doubts, as analogous observations 

 did to me. " The four trunks," he says, " which issue from 

 the ganglia have at first a clearly fibrous structure, so that at 

 the torn ends single fibiillfe appear ; but these fibres in their 

 course soon melt into a homogeneous band in which no trace 

 of fibre remains." Curiously enough, the branches given off 

 from these tninks, although they commence as homogeneous 



• Leydig, HUtoloffie, pp. 59, 185. " Die Ncrvensubstanz ist entweder mehr 

 homogen unci molekular, oder mehr von faserigem Aussehen. 



t See SiEBOLD u. KoLLIKEr's Zeiischri/t/. Wissen. Zool., v. p. 233, 360 ; and 

 vii, 99. 



