10 ARKIV FÖR ZOOLOGI. BAND 14. N:0 18. 



favour of this, the conclusion is obvious that it is caused by 

 the largeness and fewness of the ova. 



The female apparatus in the median line is not very far 

 away from the male apparatus, as may be gathered from 

 the text figure 2. It is not very long, running first strai^ht 

 horisontally forward, then bending in a sharp curve ventrally, 

 to be expanded in a horisontally placed fissure-like shell- 

 chamber of the type which is so characteristic of the cotyl- 

 ean polyclads, and then passing in a vertical course to open 

 to the exteriör. The hinder part of the apparatus is lined 

 with high epithelial cells containing a thread-like secretion. 

 On account of the large eggs the flat and round shell-chamber 

 has a large diameter, larger than is usual in the Cotyleans 

 in spite of the small size of the body. It must be consider- 

 ably spacious when expanded. In the chamber I have ob- 

 served masses of shell secretion, the granula having melted 

 together to form homogeneous bodies. 



The shell glands are of a peculiar type, the bodies of 

 the cells being nearly spherical, and the secretion granula 

 are also round, not, as usual, rod-like. 



Systematic position of the genus CJiromoplana. 



With our present knowledge of the cotylean polyclads 

 it is rather difficult to make out the relationship of this new 

 genus and it is necessary to treat this subject in considerable 

 detail. In his excellent monograph on the polyclads Lang 

 arranged the cotyleans in four families. 



1. Anonymidce, with a single, but very interesting genus 

 containing but one species, has a thin oval body lacking 

 tentacles. The pharynx is very much folded and situated in 

 the middle of the animal. There are numerous male copul- 

 atory organs situated exclusively(?) in the lateral fields of the 

 body. The female apparatus is not described by Lang. Eyes 

 occur marginally around the body and in two cerebral dus- 

 ters. The gut-branches anastomose frequently. The micro- 

 scopic weapons mentioned by Lang in the diagnosis have 

 no systematic value at all as they are nematocysts of Cni- 

 darians introduced in the body together with the food. This 

 genus has a very isolated position. 



2. The two families Pseudoceridce and Euryleptido^ can 



