54 



HYDROIDA 11 



side. The apophyses have each an unbranched hydrocladiuiii, divided b\- transverse joints into 

 segments with numerous hydrotheca;. Eacli, 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 adcanline edge. The hydrotheca-bearing interuodia 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 '/a and '/s of that 

 of the internodium. 



The gonothecte are situated on tlie stem or on the basal parts of the hvdrocladia, without 



""""■ - »<""" lOOOm. J„oo^. 



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

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



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

 the side. 



Forma typica. Short internodia with ludrotheca; in length from '/j to '/^ the internodium. 

 Forma elcganhda (G. O. Sars) slender internodia with small h\drothec£e, length as a rule from 

 Vs to '/s of the internodium. 



Material (forma typica): 



Greenland? (without further details). 



The Faroe Islands: (without further details) |= Pluiintlaria cchiintlata Winther|. 



The synonymy of the .species has recently been worked out by Bed ot (1916). It gives us an 

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



