58 Anatomy of Sag artia Schilleriana [No. 1, 



of this tube brocken off, with a slightly raised margin, is generally 

 visible near the centre of the base of each dead cell, when carefully 

 removed from its place of attachment ; it is rarely wanting except in 

 very old cells (see pi. XII, figs. 5 and 6). When, however, the cells 

 are firmly attached with their entire base the opening often becomes 

 closed up, and in time disappears altogether. Viewing the basal 

 portion of a polyzoarium each cell appears separated from the others 

 by a raised margin, while their median portions usually are slightly 

 excavated. The surface is finely porous. The usual colour of the 

 cell is pure white, occasionally slightly opac or brownish. 



h. Animal. 



There is little of special interest that I can mention with reference to 

 the animal of this species. It is enveloped in a perfectly transparent 

 mantle, which lines the internal, slightly rugous surface of the cell, 

 and appears to be firmly attached to it posteriorly and at the margins 

 of the aperture (see fig. l,f pi. XII). When the cell is broken and 

 the animal taken out, the mantle generally remains with the cell ; 

 it is therefore very difficult to trace out the connection of the 

 animal to its mantle. I have only observed a few very thin muscles 

 posteriorly, but none anteriorly, though they also may exist. Equally 

 difficult is it to observe the animal expanded, because the slightest 

 motion of the water compels it to remain closed for a long time. 

 When it protrudes out of its cell, the total length of the tentacles 

 and a portion of the collar is visible. In the retracted position 

 the V-form twisted viscera can be clearly traced through the cell- 

 membrane. In the animal, taken out (fig. 1, h) of its cell, the 

 length of the retracted tentacles (t) measures nearly one fourth of 

 that of the entire body ; they are separated by a groove from the 

 muscular larynx, in the centre of which lies the mouth ; then 

 follow the viscera, usually somewhat contorted, being thickest in 

 the middle, and by a sharp twist joining the membrane which 

 surrounds the tentacles at about one-third distance from their 

 base. At the end of the visceral cavity, there is usually seen one, 

 Beldom two or three oval, dark bodies, — probably statoblasts. These 

 viewed under the microscope, seemed to be filled with a rather 

 homogenous, granular mass, but sometimes there was a contorted, 



