BY T. HAUVEY JOHNSTON. 71 



0086 mill, broad. This knob bears the double row of hooks. 

 The rostelluni may be everted to a distance of 01 2 mm. in 

 front of the scolex, or it may be completely retracted into the 

 strongly muscular rostellar sac, which has a length of about 

 0-22 mm. The hooks are arranged in two rows, each consist- 

 ing of about ten. In most of the specimens these structures 

 have fallen off, but in the few cases in which they remain in 

 position, one can readily distinguish the presence of two 

 series. The hooks of both circlets are large, being 0062 mm. 

 long, and possess the form shown in Fig. 4. The anterior 

 attachment is long and thin, the ventral root prominent and 

 distinctly bifid, and the claw long and pointed. A few hooks 

 were seen measuring only 0-050 mm. in length, with a much 

 more prominent ventral root than that figured. 



The Strohiht. — The scolex is followed by a short, unseg- 

 mented region having a width of 0-21 mm., and a length of 

 007 mm. The segments nearest the neck are very narrow, 

 but are well differentiated laterally, the margins being 

 acutely serrate. There is an increase in width and length as 

 the segments pass backwards, the posterior angles becoming 

 more projecting ; the ratio of length to breadth of the 

 segment is about 7:1 in the anterior part of the chain, 

 whereas in segments with mature genitalia it is only 3:1, 

 the breadth at the posterior end of these segments being 

 about 0-50 mm., and the length 0-174 mm. In ripe {i.e., egg- 

 bearing) proglottids these dimensions are 0-46 and 0165 mm. 

 respectively, the ratio thus being nearly the same as in 

 mature portions of the chain. In egg-bearing segments the 

 form is somewhat different, the posterior border being rela- 

 tively shorter, and the edges much less pronounced. The 

 corners are more rounded-off, and there is less projection 

 beyond the anterior edge of the succeeding joint. There is 

 vei'y little overlapping in this portion of the strobila, and the 

 parts are readily detached. The genital pores, which alter- 

 nate fairly regu.larly, are situated on a prominent papilla at 

 about the middle of the edge of each segment. The male 



