722 Henry B. Ward, 



among such as are thick bodied and possessed of a richly developed 

 musculature. While the resemblance in one sense is certainly super- 

 ficial, yet it is the result of similar arrangement of the body rauscles 

 which resemble closely the correspoudiug structures in cestodes. 



One recognizes at first glance the one pointed end, the other 

 terminated by the rosette, and the lateral ruifles along practically 

 the entire length of the thick, undivided mass of the body. The 

 bluntly pointed end possesses a small pore, leading into a blind 

 sucker, which however is not visible in entire specimens; because 

 of this sucker the extremity which bears it may be designated as 

 the acetabular end. The opposite end is abundantly characterized 

 by the rosette or funnel. When, however, one seeks to determine 

 the morphological value of these extremities, one is greeted by a 

 conflict of opinions. 



Wagener regarded the acetabular end as anterior. Monticelli 

 (1889) adopted this view on the basis of his own studies while 

 various intermediate writers accepted the same Interpretation without 

 further investigation. The first to dissent was Spencer (1889) who 

 regarded the crenated extremity as anterior and the acetabulum as 

 posterior. The same position was taken independently by Lönnberg 

 (1891) who based his Interpretation on the most extensive study of 

 the species made up to that time and brought forward evidence on 

 this point from 1) the movements of the living animal, 2) the 

 structure of the nervous System, and 3) the slant of the spines. 

 Haswell (1902) discussed and rejected the view of Spencer and 

 Lönnberg. Finally Koeoid and Watson (1910) in a way combined 

 and reconciled these diverse views by indicating on the basis of their 

 studies, especially of the nervous System, that the acetabular end 

 was homologous with the anterior extremity of Trematoda while 

 the rosette was equivalent to the scolex of Cestoda which tho often 

 regarded as anterior must be construed in consequence of this and 

 other morphological evidence as posterior. This also agrees with 

 the observations of Lönnberg since the movements of the living 

 vvorm and the direction of the spines only indicate the rosette as 

 the physiological anterior extremity of Gyrocotyle. Watson later 

 follows this terminology, speaking of the acetabular end as anterior 

 and the rosette as posterior. 



In all of my specimens it was easy to distinguish two surfaces. 

 One of these is strongly curved, the other is nearly plane (Figs. 11. 

 12, 13), and this condition is maintained thruout the length of the 



