12 



dian line of the cestoid, as a simple brownish canal, 

 with short lateral offshoots, towards which two trans- 

 verse slightly colored lines (seminal cord and vagina) 

 run from the sides (Kiichenmeister). These are grad- 

 ually developed in each succeeding joint, until, in the 

 650 to 700th segments, they are perfect, and filled with 

 mature ova. The number of these joints have been 

 estimated from 825 in a specimen 10 feet 8 inches in 

 length (Kiichenmeister), to 2,240 (Moquin-Tandon). 



According to their position, these articulations have 

 been found to differ in size, the first ones, those near 

 the neck, being broader than they are long ; afterwards, 

 from being almost square, they become oblong ; and 

 finally their length is twice their breadth (Moquin- 

 Tandon). These latter are narrow anteriorly, broad 

 posteriorly, and overlap each succeeding one (PI. I. 

 figs. 4 and 1). The proportionate size of the different 

 segments may be judged of from the following, copied 

 from Kiichenmeister : " First, a space of 4 contained 

 50 transverse divisions, and afterwards this space 

 showed 32, 27, 22, 14, 11, 10, 9, 8, 7, 6, 5, 2, 2, 1?, 

 1? i> f? f 5 segments.'* As these joints ripen, they are 

 cast off in the faeces, &c., containing within them the 

 ripe fecundated ova. They are then known as prog- 

 lottides (Vermes rucurbitini), and are capable, when 

 cast off, of a considerable degree of locomotion, by 

 alternate elongation and contraction of the muscular 

 structure with which they are endowed ; and this point 

 has been adduced by Coulet (" Tractatus de Ascaridi- 

 bus et Lumbrico lato "), in support of the idea that they 

 are endowed with an independent existence. It has 



