56 ACTINIARIA 



muscle pennons (textfig. 65) of the "E d w a r d s i a-mesenteries" are very strong, and in transverse-sections through 

 the upper part of the reproductive tract elongated with about 50 folds. These latter are of ordinary length and 

 rather richly branched, especially in the inner and outer parts (several specimens sectioned). Between the larger 

 folds there are smaller ones (textfig. 65). The outer lamellar part of the mesenteries is commonly attached 

 close by the outside of the pennon, sometimes a little more inwards. The parietal muscles are, in comparison 

 with the pennon, not particularly strong; in transverse-sections through the reproductive tract often trian- 

 guloid (textfigs. 66, 67) with the longest folds next to the outside. There are not many folds, and they are 

 only a little ramificated ; further upwards (textfig. 67) they are more numerous, but never reach the number 

 of folds in E. vitrea. The parietal muscles are not at all, or only very slightly expanded on the column. Typic- 

 ally ciliated tracts are present. The species is dioecious. 



Remarks: The species is probably nearly allied to E. sipunculoides , but differs from this species 

 in longer nematocysts in the nemathybomes and more richly branched muscle pennons. 



Genus Isoedwardsia Carlgr. 



Diagnosis: Edwardsiinae with the column divisible into two regions, capitulum and scapus. Prox- 

 imal part of the body rounded and, as the other part of the scapus, furnished with nemathybomes. Nemato- 

 cysts of these latter long and thin. Nemathybomes scattered or arranged in several lines. Scapus with a more 

 or less well-developed cuticle. Nematocysts in the cuticle-lacking ectoderm of the capitulum small. Ten- 

 tacles 16 or more. Only one feebly developed ventral siphonoglyphe ? 



This genus, characterized by myself in a few words (1900, p. 26), is distinguished from the nearly 

 related genus Edwardsia by the absence of any trace of a physa, while a physa is always present in Edwardsia, 

 even if it is sometimes rather small. The ectoderm of the rounded, proximal part of Isoedwardsia is there- 

 fore furnished with a cuticle which is wanting in this part of Edwardsia. Both genera are also differentiated 

 from each other in this respect that the physa never contains nemathybomes in Edwardsia, while in Iso- 

 edwardsia the most proximal part of the body has nemathybomes. Possibly the presence of discontinuous, 

 ciliated streaks which are very distinct in /. mediterranea n. sp. also is of systematic importance and char- 

 acteristic of the genus, but till now we know too little about the occurrence of this structure to be able to 

 use it as a genus character. The type of the genus is I. ingolfi. Besides this species I have in the Mediterranean 

 found another one which I will call I. mediterranea. It is possible that the latter has been described before 

 as an Edwardsia, though at present it cannot be identified with any before known species. The cuticle is much 

 thicker in I. ingolfi than in I. mediterranea; in the former the muscle-pennons show about 30 folds in the 

 reproductive regions, in the latter about 70. In another paper I will describe a third species, dredged at the 

 Easter Island. 



Isoedwardsia ingolfi n. sp. 



PI i. Figs. 36, 37. 



Diagnosis: Cuticle very thick, especially in the proximal part of the body, ectoderm of the scapus 

 thin, also in the proximal part. Nemathybomes numerous, scattered on the scapus. Nematocysts in the 



