14 OS BORN. [Vol. XVIII. 



divides the animal anteriorly into separated dorsal and ventral 

 portions. The diaphragm fuses with the wall of the intestine 

 ventrally on the level of the ovary, and behind this point the body 

 is not subdivided by it as in front (see Fig. 8), which is in the 

 plane cd of Fig. 6. A diaphragm running across the body under- 

 neath the intestine is reported for Aspidogaster, Cotylogaster and 

 Macraspis, and appears to be wanting in the allied Stichocotyle. 

 The diaphragm is not a characteristic trematode organ, not being 

 found at all generally in the order. The relation of the vitellaria 

 to the diaphragm is not the same in Cotylaspis and Aspidogaster, 

 they being entirely below it in the former and, according to Staf- 

 ford, dorsal to it in Aspidogaster. The other parts are related to 

 it as in Aspidogaster. 



The parenchyma muscles are long and often branched, as noted 

 by Nickerson in Stichocotyle, and by Stafford in Aspidogaster. 

 They are most commonly found in three situations, viz., (o) run- 

 ning across from one part of the body-wall to another when these 

 come near together, e. g., in the mouth funnel, and in the sides of 

 the body between point where the diaphragm joins the side of the 

 body and the ventral sucker. (&) From the pharynx to the body- 

 wall long fibers stretch across the parenchyma, and doubtless these 

 serve as protractors and retractors of the pharynx, {c) A third 

 set of fibers are conspicuous in horizontal sections, running longi- 

 tudinally as to the body among the vitellaria, often branching. I 

 have not succeeded in recognizing the attachments of this system 

 of fibers. The visceral portions of the musculture will be taken up 

 in connection with the related organs. 



g. The Parenchyma. 



The parenchyma (Figs. 6, 7, 8, 12, etc.) fills the places around 

 the organs, being somewhat denser where it is in contact with 

 them (Figs. 7, 19) than elsewhere, as noted by Stafford in 

 Aspidogaster. It is composed of the usual branching fibers 

 and enlarged nuclei. In it unicellular glands are to be found. 

 These are most nvmierous in the head region, on the sides of the 

 pharynx, but they are also found in other parts of the body. They 

 are flask-shaped (Fig. 13), in some cases the deeper portion meas- 

 uring 20/i across, having a narrower neck which runs obliquely 



