222 Henry Leste Oszory, 
enable such large objects to make their escape. MONTICELLI 
suggested that the organs are sense organs, used in testing the 
suitability of the surface for adhesion but their structure is not 
adequately explained on that assumption, they cannot be regarded 
as specialized in the manner they are for the purpose of sensation, 
but must be chiefly glandular in character. They are however 
frequently listed among sense organs, Braun (1893), Monricezzt (1892), 
Nickerson (1902). 
Marginal organs have been found in Aspidogaster, Cotylogaster 
and Macraspis. They are not present in Stichocotyle, it is not known 
whether they are present in C. lenoiri, but presumably they are. 
Organs which may be homologous with them are found in Mono- 
stomum reticulare (WALTER, 1893). The structure of the organ in 
Aspidogaster conchicola is not adequately known but in Lophotaspis 
(Aspidogaster) vallei it closely resembles the organ of the C: insignis, 
having a narrow outlet below, a bulbous middle and a fibrous upper 
part, these parts are found in Cotylogaster as well. No details are 
on record of the structure of the marginal organs in Macraspis. 
Writers differ with regard to the details of structure of these 
organs, and perhaps the organs differ to some extent. In Lophot- 
aspis the organ is farther from the surface than in C. insignis, Looss 
regards the bulbous part as merely a bladder and the deeper fibrous 
part as made up of secreting tubes discharging into it. I do not 
find in Cotylaspis any evidence of a glandular structure in the fibrous 
part, and do consider the bulbous part as epithelial and secretory. 
MoxTICELLI regards the upper part as muscular, a retractor of the 
organ, I do not find any muscular tissue in that part but abundance 
of it lower in the same organ, so that it cannot be muscular. 
Nickerson (1902) finds the central part of the organ not hollow 
and epithelium-lined but filled with vesicular material in which no 
cells were visible; he regarded this as the secreting part, “the 
cytoplasm of glandular cells in different stages of activity”. 
m) The reproductive system. 
I) General statement. 
The reproductive system is shown in Fig.5 and 7. The single 
generative opening lies in the mid-ventral line a little distance in 
front of the ventral sucker. A very short passage leads to the 
