46 Dr. D. Bergendal on the Land-Planarim. 



trices and the course of the streaks showed that the divisions 

 had taken place at the utmost two days before. That all 

 the three pieces were together in the same pot also makes it 

 quite certain that the divisions had occurred recently and 

 spontaneously. The cephalic and posterior portions were of 

 equal length. In these divisions therefore the definite posi- 

 tion of the mouth must be of great importance. When pos- 

 terior pieces are cut away, however, no anterior abstrictions 

 occur. The histological phenomena of regeneration cannot 

 here be discussed. 



The great quantity of small portions of worms which 

 have been observed in the conservatories, although some of 

 these, of course, are formed by injuries, show that these phe- 

 nomena are by no means of rare occurrence, and therefore we 

 find among the Land-Planariae the same asexual mode of 

 increase which has recently been demonstrated in the case of 

 the freshwater forms. 



The Excretory Vascular Apparatus. 



Metschnikoff has already described two longitudinal trunks 

 in Geodesmus. On the other hand, von Kennel has since 

 investigated the same animal, and believes that the excretory 

 canals are only vacuities in the parenchyma, and hence he 

 regards it as a matter of course that in sections nothing can 

 be seen of the few flagelliferous cells. Von Kennel's obser- 

 vations, however, seem chiefly to relate to the freshwater 

 Planariaj ; in these Lang and lijima have since found regu- 

 lar excretory ducts. 



The pigmentation and the numerous bacilli of the Land- 

 Planarise have hitherto hindered the study of this apparatus 

 in the living animal. The heads in course of regeneration 

 and still unpigmented, however, furnish a pretty good oppor- 

 tunity for such observations, which may also be made on the 

 ventral surfaces of worms which have been divided by a hori- 

 zontal cut with a pair of sharp scissors. Crushed preparations, 

 which may be observed in weak solutions of chloride of 

 sodium, also furnish very good results in favourable cases. 



Hitherto I have been able to establish the following facts. 

 The apparatus presents: — (1) ciliated funnels with a very 

 strong flicker ; (2) irregular but reticulated canals; and (3) 

 longitudinal trunks. The last-mentioned are slightly undu- 

 lated and are situated to the number of two or more on each 

 side, dorsal and lateral to the ramifications of the intestine. 

 Ventral longitudinal trunks have also been observed. The 

 longitudinal trunks consist of large perforated cells and 



