90 The Genera of the PlumMlariidm, 



they rise to a considerable height, the free part about 

 equalling the adnate. The mesial sarcothecas are about as 

 long as the hydrotheca, so that the added pair of laterals are 

 much the longest of the five. Both species have a closed 

 corbula, of the same type as that of A.jpluTna. 



Halicornaria, Bush, modified. 

 {Gymnangium, Hincks.) 



Trophosome as in Aglaophenia. 



Gonangia not protected by phylactocarps. 



This genus is now taken to include only those species 

 which are destitute of any form of phylactocarp. It was 

 first proposed by Busk for all the pinnate Gymnocarpal 

 Plumularians, but modified by Allman, so as to exclude the 

 Eleutheroplea. Hincks, however, had previously proposed 

 the name Gymnangium for the group now included under 

 Halicornaria, but though the former name had the priority, 

 it has been universally passed over in favour of the latter. 

 All the species of Halicornaria described in the " Catalogue" 

 are destitute of folds in the hydrothecal internodes. None 

 of them have any trace of the posterior intrathecal ridge, 

 but in H. superha and its allies the anterior ridge is very 

 conspicuous. 



Professor Allman's H. lolumosa should be re-named, as 

 Dr. Armstrong has described a species under the same name. 



The Halicornaria i^amulifera of the '' Porcupine" expedi- 

 tion appears to me so distinct by reason of the separation of 

 the mesial nematophores from their hydrotheca3, and the 

 interposition of the accessory ramuli, that a distinct genus 

 ought to be established for its reception. Each internode of 

 the hydrocladia bears one of these appendages, and all of 

 them curve towards the distal end of the pinna, and not 

 backwards over the gonangia. 



Halicornopsis, Bale. 

 {Azygoplon, Allman.) 



Hydrocladia pinnately arranged ; a fixed anterior sar- 

 cotheca adnate to the hydrotheca, laterals absent. 



Gonangia not protected by phylactocarps. 



This genus, which was first described by me in the Journal 

 of the Microscopical Society of Victoria for 1882, differs from 



