A COLLECTION OF HYDROID.S. 



309 



by oblique joints into 5-6 regular internodes, each bearing 

 a pair of opposite hydrothec^. At the origin from the 

 hydrorhiza tlie stem is spirally ridged by one or two turns. 



Leno-th of internode O'SO mm. Width between the months 

 of an opposite pair of hydrotheca^ 0*48 nun. 



Hy drotheca. — Tubular, divergent, mouth facing outAvards 

 and contracted. The hydrotheca? are nearly in contact in 

 front {C), separate behind {B). Teeth lateral and very 



Text-fig. 9. 



Cxso. 



Ser tula rill lineal is sp.n. 



rounded and blunt, the back one being somewhat the Avider. 

 The mouth is internally constricted by perisarc ; on the 

 adcaubne surface there is a deep pit on the outside, appearing 

 as a peg on the inside (/rj) ; sometimes the pit may be more 

 or less filled up with perisarc. On the abcauline inner surface 

 there is a perisarc ridge which may be developed into one or 

 sometimes tAvo knobs (A-^). Two-flapped operculum. 



Length of hydrotheca, measured parallel to abcauline edge, 

 0-211 mm.; breadth 0-16:3 mm. 



