40 



angular intrusion into the cavity of the sucker. The central 

 part of the front of the head, between the suckers, forms a 

 broad and low cone (Fig. 1); and is unarmed in all the speci- 

 mens, but the cuticle here contains numerous small, granular, 

 non-polarizing bodies, which in life probably projected slightly 

 above the surface to give it a slight roughness. Back of the 

 suckers the head is prolonged as an inverted truncated cone 

 for a little over 0.1 mm., narrowing from 0.9 mm. at 

 the level just behind the suckers to somewhat over 0.3 mm. 

 in width at the posterior portion where the segments begin 

 (the level of truncation of the inverted cone). 



In the young and incompletely formed strobiles (Fig. 1) 

 the proglottides are all small, those next the head somewhat 

 broader than long, but soon becoming square to ovoid in 

 outline and more loosely attached to each other (moniliform) 

 than is seen in any part of the adult strobiles. These seem 

 all to be neuters, and, judging from their shape and appear- 

 ance, never become developed, and are pushed along in the 

 growth of the strobile by the formation of efficient links as 

 the head becomes older. In the fully developed strobiles 

 the neck segments are at first about a millimeter wide (wider 

 than the terminal part of head) and 0.1 mm. long; in their 

 fullest development (at widest part of strobile) they remain 

 somewhat wider than long (2 mm. wide and 1 to 1 .8 mm. long) ; 

 thence to the end they diminish in width, becoming square 

 and finally longer than broad (1.5 to 1.8 mm. long and 1 mm. 

 or less in width). The links in these fully formed specimens 

 are not sharply defined from each other, the anterior margins 

 of a given proglottis being of almost the same width as the 

 posterior margin of its predecessor, thus not permitting much 

 overlapping of the former by the latter. Without staining 

 the lines of separation between the proglottides are incon- 

 spicuous, the first impression being of a continuous surface. 

 One of the surfaces of the larger links is usually somewhat 

 convex, the opposite side showing a longitudinal concave 

 depression along the middle of the link. Genital pores 



