Nachdruck verboten, 

 üehersetzungsrecht vorbehalten. 



Contributions to the Anatomy and Histology of 

 Tlialassema neptuni Gaertner. 



By 

 H. Lyster Jameson B. A. (Dublin). 



(From the Zoological Institute of Heidelberg University.) 



With Plates 28—30 and 1 Figure in text. 



The investigations that have resulted in this paper were conducted 

 by me in the Zoological Institute of the University of Heidelberg 

 during the winter-semester 1897 — 98, and the summer-semester 1898. 

 My original object was to make an anatomical and systematic survey 

 of several collections and consignments of Gephyrea that had been 

 placed in my hands for that purpose, but in the course of my system- 

 atic work I was led aside by the fact that our common European 

 Tlialassema neptuni presented many structural characters that ap- 

 peared to be still undescribed. Accordingly I undertook a some- 

 what more detailed investigation of the anatomy and histology 

 of some of the organs in this worm , postponing my more purely 

 systematic studies for another occasion. These I hope shortly to 

 continue. 



At the outset I must express my sincerest thanks to my esteemed 

 teacher Professor Bütschli for his ever ready assistance and inspiring 

 advice, and for the friendly manner in which the apparatus and 

 material belonging to the Institute were placed at ray disposal; and 

 to Professor A. Schuberg for his generous and valuable help and 

 counsel. 



I must also record my debt of gratitude to my friend and 

 former chief Dr. R. F. Scharff, of the Science and Art Museum, 

 Dublin, by whose advice I was led to come to Heidelberg to continue 

 my zoological studies. 



ZooL Jahrb. XII. Abth. t. Morph 35 



