ACTINARIA 27 



part of the mesenteries viz. with the parietal muscles. Thus the mesenteries are provided with a continuous, 

 longitudinal muscle layer at the aboral end of the body. The ciliated streaks are always present. The state- 

 ment of Andres (1880) that they are lacking in Edwardsia claparedii, I cannot confirm, as they were present 

 in the specimens I have examined. In Isoedwardsia, at least certainly in /. mediterranea, the ciliated streaks 

 are discontinuous viz. scattered in several portions along the middle streak. A similar arrangement we find 

 in Limnactinia laevis, Scytophorus antarcticus and Parahalcampa antarctica. As far as up till now is known, 

 all Edwardsiids are dioecious. Only the 8 "Edwardsia-mesenteries" are provided with filaments and repro- 

 ductive organs. 



A classification of the Edwardsiidae, especially of the species of the genus Edwardsia, is rather difficult. 

 The different size of the nematocysts however forms quite a good character, and so do also, though in a smaller 

 degree, the structure of the muscle pennons and that of the parietal muscles. In order to get good points of 

 comparison the sections of the muscle pennons and the parietal muscles have been taken, when possible, in 

 the upper part of the reproductive region. Sections through different tracts of the body are namely of a very 

 different appearance in the same species. In order to decide whether the structure of the pennons and the 

 parietal muscles is practicable as a valuable species-character I have often reproduced figures of both 

 kinds, belonging to species from different localities. 



Sub-family Edwardsiinae. 



Diagnosis. Edwardsiidae with the physa well-developed or wanting. Scapus provided with nema- 

 thybomes. Nematocysts of the capitulum, in comparison with those of the nemathybomes, small. Inner 

 tentacles, endocoel-tentacles, shorter than the outer ones. 



The genera Edwardsia Quatr. and Isoedwardsia Carlgr. belong to this subfamily. 



Genus Edwardsia Quatref. 



Diagnosis. Edwardsiidae with body-wall divisible into three regions; physa, scapus and capitulum. 

 Physa always present, without nemathybomes. Scapus with a more or less developed periderm (cuticle) 

 with nemathybomes containing nematocysts in a rounded cavity in the mesogloea. Nematocysts in the nema- 

 thybomes long, in proportion to the breadth. Nemathybomes in 8 longitudinal lines, or more or less irregularly 

 scattered, now distinctly conspicuous upon the scapus-surface, now on a level with it. Nematocysts in 

 the ectoderm of the cuticle-lacking capitulum small. Tentacles 12 -16 or in several cycles, the inner 

 shorter than the outer (always?). Actinopharynx with a single, feebly developed, ventral siphonoglyphe 

 (always?). 



To the genus Edwardsia I have here referred the genera Edwardsia, Edwardsiella and Edwardsioides. 

 The establishment of the last genus is not justified, because, according to my examination of the type-specimen, 

 it is not different from a typical Edwardsia (Edwardsiella) . On the other hand it it questionable, if the genus 

 Edwardsiella ought to be maintained. The genus is proposed by Andres (1883) for the Edwardsiidae having 

 more than 16 tentacles. Concerning the number of the tentacles I think that it is of no great importance as 



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