﻿546 GARRISON. 



0.8 millimeter transversely, which nearly fills the posterior portion of the 

 medullary space in the median one-sixth of the segment. This joins a second 

 dilation of about equal dimensions situated at the apex of the V-shaped portion 

 of the uterine tube. In the anterior half of the segment the original four 

 to six spiral turns are still distinct. The dilated, outer walls of the coils fill the 

 dorso-ventral diameter of the medullary space, extend 0.4 millimeter on each 

 side the median line, and project prominently forward into the transverse 

 excretory canal. A number of shallow diverticula have grown out from the 

 lateral walls of both the two posterior cavities and of the anterior spiral. 



In segments 550 to 560 (fig. 16) from five to seven diverticula or branches 

 have grown out from the lateral walls of the two posterior uterine dilations, 

 extending laterally 1.17 millimeters or four-fifths the distance from the median 

 line to the ventral canals. In the anterior half of the segments the original four 

 to six coils of the spiral formation are distinguishable, and extend laterally 

 1.30 millimeters from the median line, or about two-thirds the distance to the 

 lateral canals. The anterior extremity of the spiral has expanded laterally into 

 a cavity which encroaches upon the lumen of the transverse canal. As they extend 

 toward the lateral borders, the anterior coils and the posterior diverticula 

 apparently by reason of mutual pressure and unequal growth, have more or 

 less lost the regularity of their earlier structure, some pressing toward the 

 dorsal and others toward the ventral surface and some are inclosed at their lateral 

 extremities by two adjacent and more laterally extended outgrowths. As a 

 result of this irregular development, saggital and longitudinal sections in different 

 planes present widely differing pictures, resembling in some cases the uterine 

 branches extending laterally from a median stem as in other species of Tccnia and 

 in others giving the appearance of the egg-sack formation found in other 

 genera. 



As a whole, the structure is remarkably compact, the ovic chambers being 

 closely pressed together and the partitions between them extremely thin. 



In the terminal proglottides (figs. 17, 18) the uterus fills the entire medullary 

 space, encroaches upon the transverse and longitudinal canals, and short diver- 

 ticula even press outward the muscular tissue of the cortex. A few of the 

 outgrowths reach the lateral canals without division and in the same plane. 

 Usually, their lateral extremities divide into two or three secondary branches, 

 which may again divide, the divisions taking place in any plane, but usually 

 antero-posteriorly. In a median saggital section it is sometimes possible to follow 

 a single branch from the median line, or even slightly across it, to the lateral 

 canal, but in most cases it passes dorsad or ventrad and its further lateral course 

 can be followed only in sections in other planes. Occasionally, a branch ends 

 considerably short of the lateral canals, other branches closing in around its 

 lateral extremity. 



Ova. — An outer shell could not be distinguished in either young or matured 

 ova. The embryophore is oval, with a thick, radially striated shell. Measurement 

 of fifty embryophores gave the following results in microns: 



32.5X30 



37 



X30 



35 



X31.5 



38. 9x33. 3 



37 X33. 3 



37 X31. 5 



40 



X31. 5 



36 



X29.6 



37 X33.3 



37. 5X33 



37. 5X29. 6 



38 



X31.5 



38 



X2S 



40. 7X33. 3 



36 X28 



36 X27 



37 



X33.3 



37. 



5X26 



40.7X33.3 



37 X31.5 



38 X28.5 



40. 



7X33.3 



38 



X33 



37 X28 



37 X34 



39 X29 



40 



X33 



40. 



7X33.3 



36. 5X29. 6 



37 X32 



37 X29.6 



38. 9X35 



37 



X30 



37 X30 



38. 8X33. 3 



40. 7X32 



35 



X29.6 



37 



X33 



40 X29.6 



40.7X33.3 



37. 5X33. 5 



34 



X29.6 



40. 



7X33.3 



38. 5X29. 6 



37 X29. 6 



37 X29. 6 



38 



X33.3 



37 



X30 



37 X27 



39 X33 



Maximum dimensions, 40.7X35 fj.; minimum, 35X26 /x; average, 37.8X31.1 fi. 



