742 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [24] 



in diameter and .014 mm apart cross each other at right angles in the cen- 

 ter, more or less obliquely in the vicinity of the clear spaces. These 

 transverse muscular fibers appear as curved lines with their convexities 

 towards the center of the head. The cross-sectious of the longitudinal 

 fibers, while irregular in outline, have a tendency towards triangularity. 

 The greatest diameter of any single fiber measured was .00-V m ". Other 

 larger patches were observed, but they seem to represent the coales- 

 cence of two or more single fibers. The sections of the head are at this 

 point elliptical. The cuticle is not clearly defined. The clear spaces 

 gradually lose their distinctness on account of the increase of transverse 

 fibers. At about the sixth section the transverse fibers begin to be ar- 

 ranged in fasciculi. Two of these fascicles are quite evident and join 

 opposite pairs of clear spaces in the direction of the greater diameter of 

 the section and along the longer sides of the central rectangular space. 

 The longitudinal fibers become less dense along lines which radiate from 

 the angles of the central rectangular space, while between these radiating 

 lines they appear to have become massed together more densely. The 

 clear spaces do not have definite outlines and are certainly not closed 

 vessels. They are crossed by the radiating transverse fibers and ap- 

 pear to have loose cellular or granular contents. This feature is quite 

 evident in the first sections, where nucleated cells were observed in the 

 continuation of these irregularly outlined vessels in longitudinal sections 

 of a specimen stained with ha3matoxylon. Next the two dense masses 

 of longitudinal fibers, which lie opposite and outside of the longer sides 

 of the central rectangular space, appear as two rings of dense granules 

 with a clear center, which is made up of two parts, an inner of transverse 

 or radial fibers, and an outer reticulated part. These two parts soon 

 separate. The inner one, with a deep notch in the middle, is the extreme 

 anterior end of a bothriurn, the outer reticulated part is the cuticle of the 

 posterior side of the apical disk of the head. This feature continues for 

 several sections, aud shows that the anterior ends of the bothria are 

 above the constriction and near the apex of the head. Transverse fibers 

 predominate in the vicinity of the constriction, while longitudinal fibers 

 predominate in the anterior disk. This fact was confirmed by both 

 transverse and longitudinal sections. The cuticle immediately in front 

 of the constriction is clearly defined and appears in transverse section 

 as a dense layer of fine striae. It is about .011 mm thick. 



Clearly defined sections of aquiferous vessels were not found in sec- 

 tions made at the constriction or anterior to it. 



The outline of a section at this point is quadrangular, with bluntly 

 rounded angles and concave sides; the two sides on which the bothria 

 lie are very deeply notched. Fascicles or bands of transverse fibers 

 run in a very complicated way from one side to the opposite side and 

 also diagonally from one side to the adjacent side. The longitudinal 

 fibers do not have at this point any definite arrangement. A little far- 

 ther back the corners of the quadrangular sections project and curve 



