8 



hohle" is spacious and divided into two halves by a median fold, suspended from the dorsal wall. 

 That wall consists of high cylindrical epithelium with round nuclei and very granular cytoplasma : 

 it carries long cilia. The "hintere Bauchdriise" is only strongly developed around the "Flimmer- 

 hohle", where the glandular cells extend as far as the dorsal part of the pharynx. In a similar 

 stage of development at that place is the "vordere Bauchdriise"" with its crystalline glandular cells. 



The mouth-cavity contains numerous cirrhi, here also filled with green granules. The 

 "Mundleisten"" present the following divergence: they do not travel along the wall of the 

 mouth-cavity, but they traverse the latter in strings, so that they take their course directly 

 ventrally and cut off a coecum, filled with cirrhi to the right and the left (fig. 24). 



When comparing fig. 27 with fig. 13 it becomes evident at once that here the strong 

 folds, separating in Proneomenia Weberi the mouth-cavity from the pharynx, are absent, as 

 well as the folds of the oesophagus. For the rest the salivary glands are similarly placed here ; 

 the situation of the radula also coincides. It is different with the structure of the radula. As 

 usual much has been injured in the cutting and consequently a great deal cannot be inferred 

 from the transverse sections. Fig. 26 gives a transverse section. Here it is clearly visible that 

 the radula is polystichous ; the number of the teeth is about 24, but there are also several 

 free teeth, the origin of which cannot be traced. The two middle-rows are occupied by broad, 

 flat teeth, presenting some layers, staining in different degree. The other teeth are rather long, 

 straight and slightly clubbed or hooked. Fig. 27 represents the course of the radula: first 

 proximally passing out of the radula-sac then bending ventrally, once more distally surrounded 

 by pouch b. This is an epithelial pouch; the radula enters it and folds its borders, in transverse 

 sections the pouch being therefore completely filled with teeth (fig. 28). Both large, flat teeth 

 are thus placed against the dorsal wall; the other walls are beset with the numerous other 

 teeth of which in fig. 28 only a few are given to prevent confusion. The basal-membrane which 

 connects the teeth with each other, is distinct. More distally in the pouch, the radula teeth 

 soon disappear and the epithelial pouch alone remains. In the lumen a grey, extremely finely 

 granular mass is found, which probably has filled the whole of the pouch, but has lost its 

 connection with the wall by fixation. In this mass there are a few round bodies (fig. 28). Here 

 we have the same arrangement as in Proneomenia Weberi; in the pouch most probably a 

 cuticular secretion takes place, perhaps necessar)- for the strengthening or reparation of the 

 radula-membrane. The radula itself differs from that of Proneomenia \\'eberi by the shape of 

 the teeth and their number. 



For the rest the intestine does not furnish much worthy of note. The wall of the rectum 

 is ciliated and merges gradually into the cloaca-wall ; this is characterized by the change of the 

 epithelium. The cubical ciliated epithelium of the rectum is only preserved at the dorsal wall ; at 

 the lateral wall the epithelium becomes high and cylindrical with round nuclei, and provided 

 with cilia. 



The nervous system is of a structure entirely similar to that of Proneomenia acuminata. 

 (WiRi^N 6'' pag. 81). 



The animal is mature. Large eggs, full of yolk and with a strong membrane are also found 

 in the pericardium. The genital glands which extend only a very little distance proximally 



