IITDROZOA. 87 



of sucking disc. The polypites of the allied genus 

 Stauridia are distinguished by the possession of 

 two or more cycles of dissimilar tentacles, separated 

 from one another by a considerable interval, each 

 cycle including four tentacles ; the lower row fili- 

 form, the upper whorl, or whorls, capitate, and 

 placed at right angles to one another and the 

 polypite. In Pennaria, there is a basal circlet 

 like that of Tubidariay between which and the 

 mouth of the polypite lie scattered numbers of 

 shorter tentacles, resembling those of Vorticlava, 

 In Myriothela, multitudes of wart-like tentacles 

 crowd the whole surface of the- club-shaped, soli- 

 tary, polypite. Similar to these are the tentacles 

 of Acaidis, which exhibits, in addition, a basal 

 series of long prehensile appendages. These, how- 

 ever, disappear as the organism approaches ma- 

 turity, so that this form may possibly be but a 

 young condition of Myriothela. A single series 

 of rather long tentacles, inserted as in the fresh- 

 water Hydra, arises at a short distance below the 

 moath in Tricky dr a, Clavatella, Perigonimus, 

 Bhneria, and Eudendrium. Some species of 

 these genera seem to foreshadow an arrangement 

 of the tentacles which in Hydractinia becomes 

 sufficiently conspicuous. Around the mouths of 

 the digestive zooids in this genus two rows of al- 

 ternating tentacles are placed, so close to each 

 other that they appear, at first sight, to constitute 

 a single series ; the lower tentacula, which are 

 shorter, projecting at right angles to the body of 

 the polypite, from the axis of which the upper 

 tentacles very slightly diverge. These, however, 

 have no direct connection with the long tentacular 

 appendages, arising directly from the coenosarc, to 



G 4 



