HYDROZOA RITCHIE. 821 



[point to minute knobs of chitin which form a ring on the inner 

 surface of the hydrotheca. The aperture of the hydrotheca is 

 circular, the margin entire, set at a slight angle to the axis of 

 'the hydrotheca, not everted, but almost always repeated twice or 

 >thrice, owiug to the successive regeneration of hydranths. 

 The walls of the hydrotheca are colourless and delicate. The 

 ■hydrotheca narrows gradually to the base and passes imper- 

 ■ ceptibly into the peduncle. This is of comparatively wide 

 • diameter, is about one-third as long as the hydrotheca, although 

 there is much variation, and is always marked by only a single 

 strong constriction which occurs very near its junction with the 

 stolon. Scarcely a trace of the hydranths remained, and there 

 vwas no trace of the gonosome. 



Dimensions. — 



Stolon, diameter 0042mm. 



Hydrotheca, length to diaphragm 0-34-0'39 mm. 



„ diameter 0-09-0-10 „ 



Peduncle, length 0-07-0-15 „ 



,, diameter 0-039 mm. 



Systematio Position. — These Australian specimens agree with 

 •the very short and scrappy description and with the tigure by 

 Allnian, except in a single point, that the peduncle is marked by 

 a definite constriction of which there is no sign in the American 

 examples. The hydrothecse, except for this constriction, much 

 resemble those of Lafoea dumosa, but that species is twice as 

 large, of less elegant build, with more dumpy peduncles, and is 

 anuch stronger and coarser in appearance. 



The species is Hebella-Uke, but until the gonosome has been 

 -discovered, it would be rash to remove it from the genus in which 

 it was placed by Allman. 



Locality. — Growing upon a Polyzoon from Station 57, off Wata 

 Mooli, three and a half to four miles from the shore ; depth, 59 

 to 54 fathoms; bottom, mud; 22nd March, 1898. 



I am aware of no previous record, other than that given by 

 Allman — south of Marquesas, Florida, United States, 140 fathoms. 

 The extension of range from the western shore of the tropical 

 Atlantic to the southern Pacific is remarkable. 



LICTORELLA ANTIPATHES (Lamarck). 



Sertularia antipathes, Lamarck, Hist. nat. Anira. sans Vertebres 



1816, p. 115. 

 JOaomedea antipathes, Lamouroux, Hist, polyp, corral, flexibles, 



1816, p. 206, pi. vi., tigs. \a, B. 

 X X 



