General History of the Marine Polyzoa. 293 



much the same shape, pyriform, with (in most cases) a stem- 

 like prolongation below, and are wholly adnate. A smooth 

 and solid casing envelops the lower portion ; but In the earlier 

 stages it is wanting above, and a mass of calcareous matter is 

 visible, filling the interior. In more advanced stages the 

 external envelope involves the whole structure ; but the form 

 of the original opening is in most cases indicated by a tract 

 of feeble calcification. Two of these bodies are usually 

 present immediately below the sinus, and they commonly join 

 so as to form a prominent ridge across the front wall. One 

 of thera involves in a greater or less degree and partially con- 

 ceals the suboral avicularium. 



Schizoporella scahra, sp. n. (PI. VI. fig. 4.) 



Zoao-ium incrusting. Zooecia quincuncially disposed, 

 variable, commonly hexagonal, occasionally rhomboid or 

 ovate, with raised boundary-lines inconspicuous in highly 

 calcified states, young cells depressed, punctured, In mature 

 cells the front wall much elevated towards the centre, highly 

 calcified, the surface reticulate with nodular prominences, the 

 punctures deeply sunk, a line of closely-set perforations round 

 the margin, very conspicuous in the younger cells ; orifice 

 somewhat pyriform, the portion above the articular processes 

 and hinge broad, the upper margin slightly arched, the sides 

 tending somewhat inwards ; below the hinge, where there is a 

 slight constriction, a wide sinus, narrowing downwards and 

 rounded below ; hinge marked by a very distinct line, which 

 curves upwards slightly, crossing the operculum almost 

 immediately above the sinus ; below the orifice a very promi- 

 nent umbo, bearing on its inner surface a rather large avicu- 

 larium^ with broad, rounded mandible ; peristome not raised. 

 Oacium small, shallow, depressed, wide in proportion to its 

 height, rounded above, surface smooth and glassy, oral 

 opening extremely narrow. 



Hah. Forms white masses on the stems of Hydrolda. 



Log. Port Elizabeth, South Africa (Miss Jelly). 



The appearance of the zoarium in this species is highly 

 characteristic. In its mature condition the divisions between 

 the zooecia are slightly marked ; a thick calcareous covering 

 overlies the primitive wall, the surface is reticulate, and 

 covered by a multitude of small nodular processes. The 

 avicularlan umbo Is hardly distinguishable, and both the 

 orifice and the punctures are deeply sunk in the calcareous 

 crust. 



The form of the orifice can hardly be determined accurately 



