HYDROZOAN CORALS 



155 



two sub-generic forms Labiopora and Spinipora, appears to 

 be the most widely distributed. The pores are not arranged 

 in this genus in regular cyclo-systems, but are more or 

 less irregularly scattered over the surface of the branches. 

 The characteristic feature, however, is that some of the 

 dactylozooids, or all of them, are protected by blunt 

 processes of a cylindrical shape with a deep slit down one 

 side, called by Moseley the " nariform processes." A 

 better name for them, perhaps, is grooved spines (Fig. y ;'■,). 



Each gasteropore is provided with 

 a short " shaving-brush " style, but, 

 as in Distichopora, the dactylopores 

 have no styles. 



The genus is very ^^idely distributed 

 in water of from 100 to 500 fathoms 

 in depth, and recently some beautiful 

 coloured specimens have been found in 

 shallow water off the South Island of 

 New Zealand, off Cape Horn and the 

 coast of Chili, and in the Antarctic 

 Seas. 



Sporadopora is a rare genus from 

 deep water, which has close affinities 

 with Distichopora, but it is of special 

 interest, because it has superficial 

 resemblance to a ramose colony of 

 Millepora, the colour being white, the 

 texture of the corallum being more spongy and brittle than 

 in most Stylasterina, and it has pores scattered irregularly 

 over the surface. Moreover, the resemblance is accentuated 

 by the fact that there are usually a few well-marked tabulae 

 in the gasteropores. 



The structure of the polyps and the gonophores, however, 

 prove conclusively that Sporadopora is not, in any sense, a 

 connecting link with the Milleporina. 



The remaining genera are of comparatively rare occur- 

 rence, and the only point of special interest about them is 

 the remarkable lamina or scale which protects the cyclo- 

 system in the genus Cryptohelia. 



Fig. 73. — Errina (Labio- 

 pora) aspcra. Note the 

 characteristic grooved 

 spines protecting the 

 dactylopores. :■, 5 diams. 



