554 THE ANATOMY OF INVERTEBRATED ANIMALS. 



are any cilia visible in them ; but the minute molecules which 

 float in the clear fluid which they contain are driven to and 

 fro, apparently by the contraction of the body. Infer iorly, 



X 



Fig. 157. — EcMnorhynchus.—k. Diagram exhibiting the relative position of the or- 

 gans : a, proboscis ; 6, its stem ; c, anterior enlargement of the body ; /, neck or 

 constriction between the anterior enlargement and the rest of tbe body, d; e, 

 posterior ''funnel ;" ^meniscus; h. superior oblique tubular bands; k, inferior 

 muscles of the proboscis : I, m. genitalia ; o, penis, or vulva. B. Lower extrem- 

 ity of the stem of the proboscis : a, ganglion ; 6, vascular space ; d, outer coat ; 

 c, inner wall ; e, tubular band, with the nerve ; A,/, muscular bands ; g, suspen- 

 sorium of the genitalia. C. Part of the female genitalia : a, ovary ; b b, ducts 

 leading from ovary to uterus, spermiducts (?); c, open mouth of oviduct; d, e, 

 uterus and vagina. 



the vessels all terminate in blind canals, disposed around the 

 margin of the posterior funnel. Internal to the vessel lies a 

 double layer of anastomosing muscular fibrils, the external of 

 which are circular, while the internal are longitudinal. 1 The 

 cavity of the body is filled with a fluid, in which the ova, or 

 spermatozoa, float, and, at its anterior extremity, two elon- 

 gated oval bodies depend from the parietes, and hang freely in 

 it. These are the lemnisci ; they are traversed by vessels 

 continuous with those of the parietes. The axis of the pro- 

 boscis is continued downward into an elongated subcylindrical 

 stem, rounded below, which hangs down like a handle into 

 the cavity of the body. The extremity of the stem is con- 

 nected by broad retractor muscles with the parietes, and 



1 See, for an account of the remarkable structure of these muscles, Schneider, 

 " Ueber den Bau der Acanthocephalen." (" Archiv fur Anatomie," 1868.) 



