BY K. J. GODDARD. 725 



Annidi. — Behind the " head," the body is composed of about 

 55 annali. The dorsal surface of the posterior sucker is divided, 

 by two faint lines, into three annuli. The dorsal surface of the 

 anterior sucker is marked off faintly into five or six annuli. 



Somites. — Throughout the greater part of the body the somites 

 are triannulate, the middle annulus of each being marked ofi' by 

 the presence of prominent conical papillse. Beyond this, there are 

 no other means, such as one has in P. macrothela, for mapping 

 out the somites, inasmuch as the sensory annulus is not more 

 intimately united with any one annulus than with another, and 

 thus the limits of a somite are not so graphically shown. How- 

 ever, since the sensory annulus is shown to be the middle ring of 

 the somite in P. macrothela beyond doubt, and it is hardly pro- 

 bable that one would find the middle annulus to be represented 

 by the sensory ring in one species, and the latter to represent the 

 first annulus in another species of the same genus, we may safely 

 conclude that in this species, as in P. macrothela, the sensory 

 ring is the middle annulus of the somite. The middle annulus 

 is also slightly longer than that anterior or posterior to it. All 

 the annuli bear papilliTe, but these structures are much more 

 strongly developed in the body-region than in the neck-region. 



In the body-region the sensory annulus bears six prominent 

 conical papillae, one on either side of the mid-dorsal line, one on 

 each dorso-lateral margin, and one on each ventro-lateral margin. 

 In addition to these papillae, there is a smaller papilla, similar to 

 those in the other annuli, on each side of the median ventral 

 line. 



The somitic constitution in regard to the annuli, irrespective 

 of those entering into the " head " and " acetabulum," is similar 

 to that in P. macrothela, the number of annuli being the same in 

 the body of each. 



Note on some parasitic bodies found on P. australiensis. 



In the present note, I record the occurrence of an unknown 

 Entoproctous Polyzoon, found in abundance, but in an incomplete 

 condition, on Pontohdella anstraliensis. 



