of the middle of the bcdy 



The number of collar spines is probably always forty- 

 three* These spines have been counted on a large number 

 of oercairiae and that number seemn to be specif io. Although 

 the possibility of missing *cunt by one in easily understood 

 by those who have attempted such counts, 1 feel quite safe 

 in eaying that the collar spines are forty -three in number. 

 The ventral and lateral spine* of the collar are from 0*016 

 to C.C18 mm. in length, bein& a little larger thin the 

 dorsal spines -*hioh are 0*014 san. long* The spinee are 



arranged in two alternate rows, altho the ventral ones 



n 

 show more of * clumping than the alte^&tion arrangement* 



These collar spines do no t appear until perhaps the very 

 last thing in the development cf the oercaria* Often 

 were apparently raatur* <?eroariae found withi * the redia 

 without th,e collar spin^n or at leadt only faintly 



developed. Thin probably explain* vthy eohinoatoiae eeroariae 



re^orr'ed 

 have been / without the collar pin*8 



The nurfaoe of the body in pwrtlally oovered ^iUi spine*. 

 Do really they extend Just a short distance bar^ of the oral 

 auoVer. Ventrally Umy rant^i well past the ventral ouo^er 

 where they gradually loose thoir definite size t nhape and 

 arrangement, i'i^ure 46 shows these spines as arranged on 

 the eide of the oeroaria between the oral and ventral suckers* 

 They measure in this region 0.006 mta* in length. 



The digestive system (fi(5 41) is quite easily seen and 

 of considerable size, tne intestinal caeoa extending nearly 

 to the posterior end. The mouUi is slightly ventrad, the typios 

 eohinostome position* T^ie pharynx is 0*035 mgu in length by 

 0.025 nsu in width, and is preceded by a prepharynx about 



