Haswett— Ox an apparently New Type of the Platyhelminthes. 157 
hooks (s.). The oviduct dilates below to form the uterus (ootype), which opens by a 
short passage into the genital cloaca. Opening into the uterus is a very muscular 
spherical bursa copulatrix (d.c.), the interior of which is beset with closely placed 
short spines or teeth. The vitelline glands (v.v.) consist of a number of irregularly 
arranged lobes which are situated in close apposition to the intestine. 
VI.—Arrinitigs oF ACTINODACTYLUS. 
In certain respects Actinodactylus exhibits, it seems to me, more decided 
Trematode affinities than the Zemnocephalee. But if we are to look on the former 
as a Trematode, we have to recognise that it is widely separated from any of the 
hitherto-described families of that class. It is Trematode-like in general form, in 
the presence of anterior and posterior suckers, in the absence of vibratile cilia, 
and in the general character of the alimentary canal and reproductive apparatus. 
It differs from all the described forms, not only in the possession of the marginal 
tentacles, and of a nucleated epidermis (the latter of which features it shares with the 
Temnocephalee), but in the presence of the remarkable buccal proboscis—an organ 
that is not precisely paralleled in any other group of worms. The relationship with 
Temnocephala, in spite of a certain superficial resemblance, is probably not by any 
means close : the chief point of resemblance, in addition to’ the presence in both of 
tentacles, is in the character of the integument. In the presence of an anterior 
sucker, of a buccal proboscis and of a bursa copulatrix, and in the absence of 
contractile excretory sacs, Actznodactylus difters from the Temnocephalee. 
If, then, we rank Actinodactylus as a monogenetic Trematode, we have to regard 
it as the type of (at least) a new family. The following may be given as the general 
characteristics of the family Actznodactylee so far as our present knowledge extends :-— 
Flatworms with elongate, pear-shaped, somewhat compressed body, provided 
along the lateral margins with a series of tentacles. A small anterior and a large 
posterior sucker present. Surface covered with a thin, homogeneous cuticle, beneath 
which is a nucleated protoplasmic layer or epidermis containing pore-canals and spaces. 
Mouth some distance from the anterior end. A highly extensile protrusible buccal 
proboscis armed at its extremity with a minute stylet, usually retracted within the 
muscular pharynx. Intestine a simple sac without diverticula; its walls without 
definite epithelium. No external excretory openings. A single median genital 
aperture behind the intestine. A single compact oval ovary; a receptaculum vitelli, 
oviduct and uterus. Vitelline glands consisting of a number of lobes closely applied 
to the intestine. A bursa copulatrix with muscular walls and chitinous teeth 
opening into the uterus. Two pairs of compact testes, each with a separate duct. 
A chitinous cirrus armed terminally with spines. 
