310 Dr. L. Boliraig on the 



towards one side ; its larger axis is placed perpendicularly to 

 the long axis of the body. 



The pigment-capsule of each eye is divided by a median 

 pigmental septum into an anterior and a posterior chamber. 

 I have been unable to detect any plasmatic border with nuclei 

 around the pigment-capsule ; nevertheless it does not follow 

 that it is really deficient. The pigmental septum of course 

 causes the pigment-capsule to possess two apertures, each of 

 which is closed by a lentiform cell with a distinct nucleus and 

 nucleolus which lies upon it. This cell, however, is not 

 placed close to the margin of the capsule, but leaves a small 

 space free. The cavity of each half of the pigment-capsule 

 is occupied by fine bacilli wliich stand perpendicularly to the 

 long axis of the capsule. They leave a small central canal 

 free, in which, in certain preparations, I observed extremely 

 fine fibrils. Between the bacilli there is a delicate homo- 

 geneous intermediate substance. In the vicinity, especially 

 at the margin of the capsule, there are numerous small cells 

 which are very similar to the ganglion-cells of the cerebrum, 

 and are only distinguished from them by a small difference in 

 size. They possess fine processes, of which I assume that 

 they unite with the bacilli ; but this I have not seen. These 

 cells would then have to be regarded as retinal cells. 



Enter ostoma striatum possesses four eyes, two small ante- 

 rior and two larger hinder ones. They all lie upon the cere- 

 brum, which, in contrast to all other Alloiocoela examined by 

 me, is cut off from the surrounding tissues by a very sharp 

 fine outline. Enterostoma striatum presents many peculia- 

 rities : thus, for example, it possesses an unpaired, dorsally- 

 placed ovary. In the reniform pigment-capsule two globular 

 pale structures lie close together, and these in very well- 

 preserved specimens show a distinct longitudinal striation. 

 This striation is due to exceedingly delicate bacilli, which are 

 enclosed in a delicate intermediate substance. In front of the 

 aperture of the pigment-capsule I see here two large cells 

 which produce a closure similar to that of the lentiform cells 

 of Vorticeros auriculatum. Small cells, on which I could here 

 and there detect fine processes, lie before and in the vicinity 

 of the large ones. The small cells stain, especially with 

 osmium-carmine, much more strongly than the large ones, 

 and also more intensely than the ganglion- cells of the cere- 

 brum. In one case I was able to trace such a fine process 

 into the neighbourhood of the striated globular structures. 

 I regard them therefore in this case also as retinal cells. The 

 larger pale cells, both in Vorticeros auriculatum and in Ente- 

 rostoma striatum J may, perhaps, be regarded as lens-cells, as it 



