2 ARTHUR E. SHIPLEY. 



The body tapers anteriorly, and to a slight extent posteriorly. There is no true 

 neck, the proglottides beginning immediately behind the head ; they are at first 

 extremely short from before backward, a feature they retain, though to a lesser degree, 

 even at the hinder end, where it takes some three to measure a millimetre. The 

 posterior edge of each proglottis overlaps the succeeding one to a marked extent. 



The head is conical, 3 mm. in length and 3 mm. in breadth posteriorly ; anteriorly 

 it lessens to a bluntly pointed apex. Dorsal and ventral lie the two suckers. These 

 suckers are deep, with cleanly cut edges, for the most part curled in (fig. 7), and in 

 all cases enwrapping some foreign substance, perhaps a portion of the mucous 

 membrane of the host. 



The impressed line running along the whole body, referred to by Baird, is only on 

 the ventral surface, and is due to the median opening of the reproductive organs and 

 of the uterus. 



The nervous system consists of two very conspicuous nerve cords, which lie parallel 

 with the longitudinal excretory canals, and about one quarter the distance of the latter 

 from the edge of the proglottis outside the canal. The cords fuse together in the head. 



The longitudinal canals of the excretory system are also conspicuous, and are 

 surrounded by thick walls ; they break up into an anastomosing tangle of ductules in 

 the head. There are also small canals which lie close under the surface at the edges of 

 the proglottides, usually two at each side (fig. 2), but they also break up from time to 

 time into twisting branchlets. The overhanging edges of the proglottides, especially of 

 the posterior ones, are very richly supplied with water- vascular tubules. It is possible 

 that these may have a certain hydrostatic action, and serve to erect these free edges 

 when fluid is directed into them. 



The confused meshwork of muscles in the head straighten themselves out in the 

 neck and fall into regular rows. Of these there are six or seven dorsally and six or seven 

 ventrally (fig. 2), but at the sides the rows tend to merge and lose their distinctness. 

 Each row is separated from the next by very clear and distinct connective tissue 

 fibrils running parallel with one another. The muscles in these rows consist of bundles 

 of various sizes containing from six or seven up to fifteen or twenty fibrils. Eunning 

 between every two or three of these bundles are some slight and radially arranged 

 connective tissue fibrils, which, with the concentric fibrils of the same nature, serve to 

 divide up the tissues into a series of little squares. No muscle fibres penetrate tlie 

 parenchyma within the central area, bounded at the sides by the nerve cords and 

 dorso-ventrally by the innermost layer of muscles. 



The penis is conspicuous and very muscular, it opens in the anterior edge of the 

 proglottis just where it joins the one in front, and is concealed by the overlapping end 

 of the preceding proglottis. Close behind it opens the vagina, and behind this again the 

 uterus, all in the middle ventral line. There is a large vesicula seminalis. 



The testes are scattered throughout the parenchyma of the central part. The 

 ovary is rather branching ; it lies towards the posterior end of each proglottis, is deeply 



