144 PROF. W. M. SMALLWOOD ON HYDROIDS [Jan. 18, 



number is not constant, but ranges from 16 to 19. Their distri- 

 bution is as follows : — Of eight which are constant in position, 

 two Occupy the median plane, one of them behind the rhinophores 

 about one-sixth of the distance between base of branchial plumes 

 and rhinophores, the other in front of the plumes about one-fourth 

 of the same distance. The remaining six are arranged in pairs 

 near the median plane, one pair a little in front of the rhinophores 

 and distant from each other about the thickness of a papilla ; a 

 second pair slightly in front of the posterior median papilla and a 

 little further apart than the anterior pair ; the third pair nearly 

 as much behind the plumes as the posterior median papilla is in 

 front of them ; these are still further from each other. 



In addition to these eight papillae, there are on the dorsum 

 near its lateral margins from eight to eleven papillae. There are 

 four on each side, or four on one side and five on the other, or, 

 finally, five on one side and six on the other. 



Text-fi^. 10. 



Tolycerella zoobotryon, sp. n. 

 Dorsal view. Magnified 8 diameters. 



The ground-colour is whitish, mottled with light brown arranged 

 in irregular splotches. A less abundant darker brown is disposed 

 in streaks across the lighter brown. The foot is white and with- 

 out any colour markings. Its margin, as well as the tips of the 

 papillae, is translucent. 



The foot is smooth and slightly notched anteriorly. The 

 mouth is T-shaped. The anal opening is subcentral in position, 

 and the excretory orifice is just posterior to it, both being sur- 

 rounded by the gills. 



The gills consist of four or five more or less irregularly branching 

 plumes. 



When at rest the body is shortened, the tentacles drop back 

 alongside the body, and the rhinophores lie on the dorsum. The 

 papillae, which are constantly in motion when the animal is 

 crawling, are bent clorsally when it is at rest, and are often knobbed. 



