On Stichocutjrie nephropis Cunningham, a pnrR.'>itc of the American lobster. 461 



distinguished a. taint irre{.;ular reticulum, which is in intimate relation 

 with the fibres ami flic nuclei. Whether these nuclei are in any way 

 connected with the muscle tibres of the sucker I have not been able 

 to determine. 



Pareiichyiiia. 



'Jhc parenchyma of the l)ody presents a condition similar to that 

 of the parenchyma of digenctic Trematodes generally. It surrounds 

 and sup[)orts all of the internal organs as a more or less open 

 meshwork with nuclei distiùbuted through it. In the interior portions 

 of the body these nuclei are less numerous and of smaller size than 

 in the peripheral portions just beneath the musculature of the body- 

 wall (PI. 29, Fig. 4). 



Concerning the intimate structure of this tissue and the origin 

 of the vacuolated condition I have made no observations which enable 

 me to add anything to what is already known concerning them. 



Digestive System. 



The digestive system (PI. 29, Figs. 3-6; PI. 30, Fig. 19; PI. 31, 

 Figs. 22, 23, 25 and 26) is simple and made up of three portions, 

 the pre-pharynx, the pharynx and the simple intestine. There are no 

 glands or other appendages connected with it. 



The pre-pharynx (PI. 29, Fig. 5) may be divided into two por- 

 tions, an outer, more or less distinctly cup-shaped vestibule and a nar- 

 rower inner part, which lies immediately in front of and surrounding the 

 anterior end of the pharynx. The relations of these parts are shown 

 in PI. 29, Fig. 5. The pharynx is capable of being protruded far 

 forward within the cavity of the pre-pharynx, which is accordingly 

 extremely variable in form. The Cuticula, which is continuous with that 

 covering the whole exterior surface of the body lines the pre-pharynx, 

 becoming somewhat diminished in thickness within the inner portion 

 of the pre-pharyngeal cavity. It also extends backward through the 

 pharynx as far as its posterior end. 



The outer portion of the pre-pharynx is a somewhat imperfectly 

 formed, but nevertheless distinct, mouth-sucker. It is of the simplest 

 type embracing only three sets of muscle-fibres. Two of these are 

 continuous with the circular and longitudinal muscles of the body- 

 wall. The third set consists of fibres radiating through the paren- 

 chyma of the anterior [>art of the body from the wall of the pre- 

 pharyngeal cavity to the external body-wall. By the contraction of 



