Dr. D. Bergendal on the Land-Planarim. 49 



usually stain very strongly, and hence they cannot be well 

 investigated. The observation of the living animal, however, 

 fully establishes the interpretation of these papillae as tactile 

 organs. 



In the above-mentioned pits, which are nearly spherical, 

 the epithelial cells are much smaller, but they also stain 

 strongly and can scarcely be washed out. From the anterior 

 part of the brain, which rather forms a nervous plexus, strong 

 nerve-branches run to the pits. The nerve-fibrils become 

 thicker, and immediately beneath the pit we see a club- 

 shaped bundle of long spindle-shaped and bacillar terminations 

 of fibres. From these, small prolongations, which are of 

 capillary fineness even under very high powers, run outwards 

 between the cells of the epidermis. How they behave when 

 there I cannot yet say. They are not connected with the 

 rather strongly vibrating cilia which occupy the bottoms of 

 the pits. Around this nerve-mass are placed larger^ curved, 

 fibriform granular structures, which pass to the lateral epithe- 

 lial cells of the passages leading to the pits and agree in their 

 appearance and reactions with the secretion-products of the 

 glands. Motile cilia can hardly perhaps be interpreted as 

 nerve-terminations, and therefore it seems probable that there 

 are sense-hairs in the bottom of the pits among the cilia. The 

 groups of strongly motile cilia of the freshwater Planariae 

 discovered by von Kennel have been regarded by lijima as 

 tactile organs, which can hardly be correct. They seem, 

 however, to agree with these pits in Bipalium^ and ought, 

 perhaps, to be interpreted as olfactory organs or organs of 

 taste. 



Eyes occur in this species in enormous numbers. They 

 form a zone of three or four rows near the margin of the head, 

 and are also placed on the sides (not on the back) of the 

 whole body, even to the hindermost end. The largest eyes 

 are situated just behind the head. The eyes nearly agree in 

 structure with those of the other Triclades. The crystalline 

 cone is formed in the same way of several nucleated clavate 

 cells. The nucleus seen by Moseley in the hindmost part of 

 the eye belongs to the pigmentiferous cell. Nerves run to the 

 eyes from the superficial nerve-plexus. Sometimes I have 

 observed a gangliniform enlargement beside or in front of 

 the eyes. 



As regards other organs and structural conditions, I give 

 here only the following remarks : — The whole body is pro- 

 vided with cilia. Between the ordinary epithelial cells we 

 see here and there groups of slenderer bacilliform cells which 

 may possibly be sense-organs. The rhabdites are of two 



Ann. & Mag. N. Hist. Ser. 5, Vol. xx. 4 



