42 



C. M. CHILD. 



rapidity of tentacle-development of different parts of the disc 

 characteristic of oblique discs (cf. pp. 35-38), the tentacles appear- 

 ing earliest on the most distal portion and latest on the most prox- 

 imal portion of the disc. A case of this sort is shown in Fig. i 5. 

 The later history of these oblique discs is similar to that of partial 

 discs formed after transverse incisions, and during the change in 

 position of the disc the obliquity gradually disappears as in other 

 oblique discs and the result is an animal of usual shape. 



But when the angle between the incision and the transverse 

 plane is greater than 50°-6o° {c, Fig. 1 3) the results differ from 



^ 



/5 



^J 



those described and in some cases permanent lateral discs are 

 formed borne on a small column which arises as a branch from 

 the side of the original body. As the plane of the incision ap- 

 proaches the longitudinal axis of the body the incision approaches 

 a longitudinal direction and the process of wound-closure ap- 

 proaches that occurring after a longitudinal incision. The course 

 of an oblique incision approaching the longitudinal direction is 

 indicated in Fig. 16. After an mcision of this kind the wound 

 in the body-wall closes longitudinally by approximation and 

 union of the cut margins (Fig. 17), but the oblique slip of tissue 

 which was separated distally from the body-wall but is still con- 

 nected with it proximally is not included in the closure and its 

 cut margins also close longitudinally and independently of the 



