A COLLECTION OF HYDKOIDS. 341 



Length about 1*10 mm., greatest breadth 0"34 mm., height 

 of teeth about 0"08 mm. Distance of upper edge of diaphragm 

 from base 0"119 mm., diameter of opening in diaphragm 

 0'017 mm., diameter of diaphragm 0"128 mm. 



Hydranth. — About 14-10 tentacles; nematocysts 4"6 /u in 

 length and I'-i^ in breadth. 



Gonosome. — Gonangia long and cylindrical, arising from the 

 stolon by short peduncles with 2-4 annulations. Opercular 

 surface flat. 



Length of gonangium 1'50 mm., breadth 0"31 mm., diameter 

 of operculum 0*26 mm., length of peduncle about 0'82 mm. 



Free- swimming meduste are undoubtedly formed, and stages 

 in their development can be observed in the various gonangia 

 on the colony. It is not, however, possible with the available 

 material to describe the general character of the medusa. 



(33) Lafoea scandens Bale. 



Lafcea scandens B(dc. 'Proc. Linn. Soe. N. S. Wales,' vol. iii. 



1888, p. 758, pi. xiii, figs. 16-19. 



This hydroid has been found on two occasions growing on 

 Thuiaria tub ul if or mis. The yonano-ium has not been 

 seen, but the trophosome of the Natal hydroid does not appear 

 to be separable from that of scandens from Port Stephens 

 and Port Jackson, E. Australia, described by Bale. 



Tegphosome. — The hydrorhiza is a stolon creeping on the 

 back of the hydrocaulus of the sertularian. Sometimes the 

 stolon shows a tendency to be jointed. 



Diameter 0"109 mm., thickness of perisarc 3'3^. 



Hydrocaulus. — As distinct from the creeping stolon, it is 

 represented merely by the pedicel of the hydrothec^. This 

 pedicel may or may not be jointed into two. 



Diameter 0"067 mm., length 0-092 mm. ; when jointed, 

 proximal joint, 0"039 mm., distal joint 0'054. 



Hydrothecte. — Tubular, long, straight or slightly curved, 

 margin somewhat everted. The hydrothecse generally alternate 

 right and left with the hydrothec^ of the sertularian. 



