NEW- ZEALAND ACTINIARIA. 531 



often passes down the bod}', when the aboral end assumes the 

 appearance of a terminal orifice, though no sucli orifice really 

 exists. So far as 1 can make out, there are no perforations in 

 any part of the body-wall. The disc and capitulura can be 

 completely and quickly invected, when the body becomes clavate 

 or fusiform, with six prominent crest-like ridges above, the 

 crenations between these corresponding with the insertions of 

 the six pairs of perfect mesenteries. The tentacles are 

 transversely wrinkled when contracted, and they can be reduced 

 to mere wart-like processes. The six alternate tentacles of the 

 inner cycle, which spring from the endocoeles of the perfect 

 mesenteries, are frequently more prominent than the other six 

 which spring from the endocoeles of the imperfect mesenteries, 

 being held more forward and upright. The tentacles of the 

 outer cycle spring from the exocoeles. The body is clothed with 

 a thin, rough, greyish cuticle, which is thrown off in captivity. 

 The acontia consist of a tough, transparent, homogeneous, fine, 

 thread-like axial baud surrounded by granular tissue composed 

 of ciliated cells, among which the nematocysts lie packed closely 

 together with their outer ends slightly directed towards the free 

 end of acontia. The acontia are O'l mm. in diameter, and the 

 nematocysts of the acontia 0'072 mm. in length. "When the 

 body-wall is ruptured the long, white, thread-like acontia (with 

 free ends) stream forth freely. The nematocysts are then 

 discharged and the axial band only withdrawn. Sections through 

 the body show six pairs of perfect mesenteries (macrosepta) 

 bearing strongly developed, circumscribed retractor muscles, 

 characteristic of the HalcampidcB. Six pairs of imperfect 

 mesenteries (microsepta) alternate with the six pairs of perfect 

 mesenteries. The mesenteries and acontia can be clearly seen 

 with a lens through the thin, transparent body-wall of an expanded 

 individual. 



I am indebted to my friend Mr. H. B. Kirk for the first 

 specimens of this extremely interesting little species. Two very 

 fine specimens were discovered by him at Ohiro Bay, while 

 collecting calcareous sponges, and were placed in my hands 

 26th Sept., 1893. One of these was conspicuous in having a 

 beautiful bright crimson capitulum, the colour shading ofi" on the 

 scapus. 



The young of this species are not parasitic like the young of 

 Halcampa. I have often found full-grown individuals with 



