90 A. OKA. 



diagnostic cliaracters of the present species to which I give the name 

 of Pect. geJatinosa, are as follows : 



Colony oval, hyaline; branches of cœnœciuni di- 

 chotoinous ; no septa between the eel 1 s ; ec tocys t gel ati - 

 nous, fills ap the space; between the branches, forms a 

 common base for many colonies; invaginated fold 

 obsolete; alimentary canal straight when retracted; 

 tentacles 90-98; statohlast saddle- shaped , curved in 

 two axes; marginal spines minute, only seen under a 

 moderate power of microscope. 



The colonies grow among aqueous plants and on the underside 

 of floating logs just below the surface of water, and seem to 

 flourish in direct sunshine as well as in shadow. They are found 

 together in a large number forming a luxuriant mass of gelatine, 

 sometimes two metres in length. The outline of each cohjny is 

 irregularly hexagonal on account of mutual pressure. The gelatinous 

 ectocyst of neighboring colonies coalesce, and form a common base 

 2-3 cm. thick. 



This species furnishes very favorable materials for the student of 

 this group of animals, the transparency of its gelatinous ectocyst, the 

 unequalled large size of the polypide and the promptness with which 

 they evaginate, giving great faciUty for investigation. 



The general a{)pearance of a group of colonies is represented in 

 natural size in fig. 1, PL XVII. The color of the cœnœcium and 

 tlie lopliopiiore is sligiitly yellowish, the œsophagus and the stomach 

 are brown, and the rectum usually contains dark grayish refuse 

 matter, otherwise of light brown color. 



The largest colony that I have seen me.isured 7 cm. in diameter . 

 The polypides are most crowded and in fullest vigor along the 

 margin of a colony, aiid much less crowded in the middle portion^ 



