T^ENIA SOLIUM. Ill 



Tlie calcareous corpuscles 1 reach about to the middle of the 

 sucking discs ; they are few on the head, usually very small, and 

 appear as if composed of two or three concentric layers. To 

 obtain a clear view of them the focus must be altered in various 

 ways. As a general rule, it may be admitted that the head of 

 cestode worms in the second stage contains more corpuscles, 

 and these of larger size, than that of the mature Taenia. In 

 examining, on the head of a Ttenia, a space as large as the field of 

 my PlossPs microscope (eye-piece 1 ; object-glasses 1+2 + 3), 

 I counted 60, 70, to 110 calcareous corpuscles in this space. 



The slender neck, of about 6"' in length, exhibit 110 traces of 

 transverse striation or segmentation. The calcareous corpuscles 

 are somewhat more abundant, and also in general larger than in 

 the head. 



Behind the neck commences the true, jointed body of the 

 Taenia, in which I counted 825 segments in one case, and in 

 which the specimen was ten feet two inches in length. The 

 proportionate size of the segments, which gradually increase 

 posteriorly, will be best seen from the following statements : 

 First, a space of 4"' contained 50 transverse divisions, and after- 

 wards the same surface showed 32, 27, 22, 14, 11, 10, 9, 8, 7, 6, 

 5, 2J, 2, 1, 1, |, f, |, \ segments. In length the segments in- 

 creased gradually from " to 1"' ' . In this species, as in all 

 Cestoidea, contact with water causes the emission of Dujardm/s 

 sarcode in oleaginous drops. 



Sexual organs. From the 280th segment onwards, there is 

 seen, in the median line of the Cestoidea, a simple brownish- 

 yellow canal, with short, lateral offshoots, towards which two 

 transverse, slightly coloured lines (seminal cord and vagina) run 

 from the sides. At the 317th segment commence the first indi- 

 cations of the alternating port genitales, in the form of promi- 

 nences; at the 350th the pores themselves become distinct. 

 Between the 280th and 400th segments, an accumulation of small, 

 yellowish, loose aggregations of corpuscles lying in the parenchyma 

 is seen gradually becoming more distinct; from the 420th seg- 

 ment onwards, the upper end of the median canal (uterus] becomes 



1 Von Siebold certainly lays too much stress upon these in the determination of 

 species, which is much the same as if we were to impute to carbonate of lime the pro- 

 perty of acquiring as many forms of amorphous, uncrystalline deposition, as there are 

 species of animals and their respective Ttenice. 



