WERNER MARCH AND 41 



The second pair of muscles corresponds probably to the elements 

 which Graber assumed to be a second pair of nerves; their diameter 

 is about the same as in those of the first pair; they are attached at 

 the sides of the posterior parts of the cyst, extending backwards 

 almost parallel to one another, and finally are found to be inserted 

 at the sides of the opening of the terminal tube, in the furrow be- 

 tween the eighth and ninth abdominal segments. The action of these 

 muscles consequently is directly opposed to that of the first pair, 

 and displaces the organ posteriorly. 



The two pairs of muscles described are the most important and are 

 attached at the lateral walls of the cyst; the two following pairs are 

 attached to the posterior border of the ventral side of the cyst. Of 

 these, the third pair, more exteriorly located, is formed by two di- 

 vergent muscles which are inserted at the sides of the ventral body 

 wall, somewhat behind the sulcate prominence bearing the anus. 

 The two muscles of the fourth pair are also attached to the ventral 

 body wall, near the median line, in front of the lip-like hook-bearing 

 expansion. Hence it appears that these two pairs of muscles pull 

 the organ in the ventral direction, between the two large principal 

 tracheae. 



Membranous ligaments are also described by Paoli. In addition to 

 the four pairs of muscles and the terminal tube, the organ is held in 

 position by membranes, the largest of which has the shape of a coni- 

 cal cap involving the capsule anteriorly and attached to the poste- 

 rior extremity of the dorsal blood vessel, which terminates not far 

 from the limit between the seventh and eighth abdominal segment. 

 Other membranes, one on each side, envelop the basis of the muscles 

 of the second pair, but Paoli was not able to find the insertion of 

 their free end. 



Concerning the nerves belonging to the organ, Graber claimed 

 that it was richly innervated, describing two large nerves which 

 formed ganglion-like masses near the capsule. These nerves, how- 

 ever, are muscles, according to Paoli, which are slightly inflated at 

 their base. It is to be noted, however, that the ganglion-like swell- 

 ings were reported by Graber not for the large nerves, but for the 

 first thin pair. Paoli found two nerves which anastomose and fuse 

 to a short tract, further on redividing into two branches, one more 



