234 W. N. F. WOODLAND 



Synodontis schall, Bloch-Sclmeider 1 801 , and A u c h e n o - 

 glanis occidentalis, Cuv. and Val. 1840. Since I have 

 not examined personally the Sanguinicola armata and 

 S. inermis of Plehn, I am unable to say, especially in view 

 of the somewhat diagrammatic figures and, in the case of 

 certain organs, discordant accounts of the anatomy of these 

 two species, whether the Sanguinicola from the Sudan is a 

 distinct third species or not, but its structure is evidently 

 sufficiently similar to enable me to venture to correct and 

 amplify in some respects the descriptions supplied by Plehn 

 and to furnish some additional evidence in connexion with the 

 possible affinities of this organism. 



My material consisted in all cases of specimens already 

 stained and mounted in balsam. Twenty were from A u c h e n o- 

 glanis occidentalis and fourteen (including one ver}'- 

 young form, three cut into horizontal and transverse sections, 

 and four which J. lost during restaining but which I had pre- 

 viously examined) from Synodontis schall. In length 

 the adult or nearly adult specimens varied between 647-4 and 

 1,228-4 microns in length, and all were of the 'armed' (i.e. 

 bearing spinelets on the edge of the body) type. 



One external feature which Dr. Plehn has not described for 

 S. armata and S. inermis is the presence on the surface 

 of the body which does not carry the genital openings of 

 a furrow or groove, shallow over the greater length of the 

 body but deep posteriorly and terminating just anteriorly to 

 the hind end of the animal in a distinct pocket (PI. 18, figs. 3, 7, 

 z, Y, X, w, v). This furrow or groove is formed by the inturning 

 and posterior fusion of the edges of the body, is apparently 

 a permanent formation judging by the posterior pocket, and 

 is similar in form to the similar body grooves to be found in such 

 Trematodes as Hemistomum clathratum and the male 

 Schistosoma, but differs in that it does not contain the sexual 

 apertures and therefore cannot be of use in copulation. The 

 edges of the body which border this furrow contain the spinelets ^ 



^ If mounted specimens of Sanguinicola be not well flattened out, 

 spinelets will appear to be absent on the ' edges ' of the body and can only 



