54 



HYDROIDA II 



side. The apophyses have each an unbranched hydrocladium, divided by transverse joints into 

 segments with numerous hydrothecae. Each, or more rarely, every alternate internodium on the 

 hydrocladium has on its distal half a hydrotheca entirely fused down its one side with the inter- 

 nodium, or more rarely having a low free adcauline edge. The hydrotheca-bearing internodia are also 

 distally furnished with a median pore, proximally with a median pore having raised edges, through 

 which the naked sarcostyles pass. The length of the hydrotheca varies between L / 2 and '/s of that 

 of the internodium. 



The gonothecae are situated on the stem or on the basal parts of the hydrocladia, without 



2 00 m. 6oo»> ,1000m. looom. 



Fig. XXIII. The distribution of Kirchenpaueria pinnata in the Northern Atlantic. 

 In the hatched regions a common occurrence is stated by the literature. 



special protective organs. They are oval to pear-shaped, smooth or spiny, often much flattened from 

 the side. 



Forma typica. Short internodia with hydrothecae in length from '/, to 72 the internodium. 



Forma elegantula (G. O. Sars) slender internodia with small hydrotheca;, length as a rule from 

 J /s to 78 of the internodium. 



Material (forma typica): 



Greenland? (without further details). 



The Faroe Islands: (without further details) [= Plumularia echinulata Winther|. 



The synonymy of the species has recently been worked out by Bedot(ic.i6). It gives us an 

 interesting insight into the variability of a species, and throws a sharp light upon several of the 



