48 THE ANTHOZOA 



remaining members of the real second cycle 2, to which are 

 added the four couples 2", and so forth. The suggestion is in- 

 genious ; it can hardly be said to be proved, but may be provision- 

 ally accepted, and the Sicyonidae may be considered as offshoots 

 of the six-rayed Actinians. The reader will not fail to notice the 

 resemblance between Tealia, Polyopis, and Sicyonis. They are 

 clearly more nearly related to one another than the following, and 

 are offshoots from the fully formed biradial type : — 



The genus Peadiia has no sulculus, but a large and modified 

 sulcus with a conspicuous protuberant lip, the conchula. It has 

 ten couples of mesenteries — six couples are complete, two couples 

 being directives. They correspond in number and muscular 

 arrangement to the definitive primary C3'cle of Actinia, and are 

 doubtless homologous with them. The four remaining couples 

 are incomplete, have no filament, and do not bear gonads, but are 

 very muscular. One couple is found in each sulco-lateral and lateral 

 chamber, but there are none in the sulculo-lateral chambers. 

 Peachia, then, is a six-rayed Actinian with two cycles of mesen- 

 teries, but the sulculo-lateral couples of the second cycle are sup- 

 pressed. 



The Monauleae of Her twig are represented by the single 

 species, Sciitophorus striatus. It has only one stomoda^il groove 

 (the sulcus), fourteen tentacles, and seven couples of mesenteries 

 (Fig. XXII. 4). 



This may easily be explained by reference to a larval Hal- 

 campa. The mesenteries are numbered in the order of their 

 succession in Halcampa, and to the six couples of the primary cycle 

 two mesenteries are added marked x, x, whose muscle banners are 

 so disposed that they seem to form couples with the ascular 

 directives. 



Gonactinia prolifcra, a remarkable form found on the coasts of 

 Norway and recorded from Falmouth, has sixteen tentacles, a 

 sulcus and sulculus, and sixteen mesenteries (Fig. XXII. 5). 

 Of these eight are macromesenteries, are complete, and in the 

 arrangement of their muscles agree with the Edwardsia tvpe. 

 The eight others are incomplete micromesenteries ; there is a couple 

 in each sulculo-lateral chamber, their muscle banners vis it vis ; one 

 micromesentery in each transverse and sidco-lateral chamber, their 

 muscle banners so disposed that they face the sulco-lateral and 

 sulculo-lateral macromesenteries and seem to form couples with 

 them. Only the four lateral macromesenteries bear gonads, and 

 in immature forms these are the only four which bear filaments. 

 In this case the derivation from an Edwardsia form is obvious, 

 and it may also l)e observed that if the u])per members of the two 

 pairs of mesenteries marked //, // in Fig. XXII. 5 are taken away, 

 the arrangement and number of mesenteries resembles Scy tophorus. 



I 



