_Zooecia._ Although the zooecia are distinctly tubular as a whole, two longitudinal axes may be distinguished in each, for the tip is bent upwards in a slanting direction, bearing the orifice at its extremity. The main axis is, however, at right angles to the dorso-ventral axis, and the dorsal surface, owing to the position of the aperture, can always be readily distinguished from the ventral, even when the position of the zooecium is vertical. Each zooecium tapers towards the posterior extremity. Parietal muscles are always present. [Illustration: Fig. 36.--Structure of _Paludicella ehrenbergi_ (A and B after Allman). A=a single zooecium with the polypide retracted. B=the base of the lophophore as seen from above with the tentacles removed. C=the orifice of a polypide with the collar expanded and the tentacles partly retracted. _a_=tentacles; _c_=collar; _d_=mouth; _e_=oesophagus; _f_=stomach; _g_=intestine; _k_=parieto-vaginal muscles; _p_=parietal muscles; _o_=cardiac part of the stomach; _r_=retractor muscle; _s_=funiculus.] _Polypide._ The most striking features of the polypide are the absence of any trace of a gizzard and the highly specialized form assumed by the cardiac part of the stomach. There are two funiculi, both connecting the pyloric part of the stomach with the endocyst. The ovary develops at the end of the upper, the testis at that of the lower funiculus. _Resting buds._ The resting buds are spindle-shaped. Kraepelin recognized two species in the genus mainly by their method of growth and the number of tentacles. In his _P. mülleri_ the zoarium is always recumbent and the polypide has 8 tentacles, whereas in _P. articulata_ or _ehrenbergi_ the tentacles number 16 and upright branches are usually developed. It is probable, however, that the former species should be assigned to _Victorella_, for it is often difficult to distinguish _Paludicella_ from young specimens of _Victorella_ unless the latter bear adventitious terminal buds. The gizzard of _Victorella_ can be detected in well-preserved material even under a fairly low power of the microscope, and I have examined specimens of what I believe to be the adult of _mülleri_ which certainly belong to that genus.