196 ERNEST WARREN. 



It is far fi'om clear how fertilisation takes place^ since the 

 gonophore is surrounded by a thick perisarc, and the eggs, 

 after they have become charged with yolk-globules, segment 

 and ultimately form planula? while still inside the parent 

 gonophore (PL XXXIII, fig. 3, P/.). The planulas are solid, 

 and consist of an outer columnar epithelium, within which is 

 a granular mass densely crowded with yolk. During matura- 

 tion the eggs are surrounded by follicle cells (PI. XXXIII, 

 fig. 4,y?. ; and text-fig. 4, a,^.) , On the formation of the planulge 

 the follicle cells disappear, but a layer of ectoderm cells 

 persists on the ectotheca and also covering the spadix 

 (PI. XXXIII, fig. 3, ec^.). 



(5) Systematic position. — As it has been seen, the re- 

 productive bodies are fixed gonophores, and consequently 

 the present species is at once marked off from Perigouimus, 

 where free medusEe are produced. It agrees with Bimeria 

 and Garveia in having fixed gonophores. It differs, how- 

 ever, from Bimeria in habit, in not having the perisarc 

 continued over the base of the hypostome and tentacles, and 

 in having the spadix unbranched. It also differs from 

 Garveia in habit and in the structure of the gonophore. 



In the gonosome the species agrees with Hinck^s definition 

 of Atractylis arenosa (Allman\s Wrightia arenosa), 

 in which a special point is made that although closely allied 

 to Perigonimus it differs in having fixed gonophores. 



The polyp of this species is, however, very little like that 

 of Wrightia arenosa. The average number of tentacles is 

 about fifteen instead of about nine ; the tentacles are not 

 muricated, and the polyp is scarcely at all retractile into the 

 upper cup-like portion of the stem. Also, the extrusion of 

 the eggs from the gonophore into a gelatinous sac, which 

 Hinck's describes in Atractylis, has not been observed in 

 the present species ; and in fact it probably does not occur, 

 since fully-developed planulge are found in the unruptured 

 gonophore. The mode of fertilisation is problematical. 



The general appearance of a colony is like that of Perigo- 

 nimus; the endoderm of the hydranth is red, as in several 



