36 



ACTINIARIA 



4 



wliite spot and often another one at the base of the tentacles. Oral disc yellowy-white, with brown streaks 



nrnmifl the mouth. 



Dimensions in very extended state to about 6 cm. long, commonly shorter, breadth 0.3 — 0.4 cm. 

 Occurrence. Sweden. Bohuslan, Vaderoarne 8 — 10 fms., sand (Carlgren, Oestergren) together 



with E. longicornis, but less frequent than tliis species. — 60 fms. (Gunhild-Exp. 1878). 



Exterior aspect. The physa is well-developed. 

 The scapus is provided with a thin, sUghtly adherent 

 periderm, commonly of a dirty-grey colour. The in- 

 sertions of the mesenteries are conspicuous, apparently 

 neither the scapus nor the capitulum are polygonal, 

 at least not in extended state. The nemathybomes 

 are not visible to the naked eye, wherefore the scapus 

 seems to be devoid of them. They do, however, ap- 

 pear in great numbers and are mostly irregularly 

 packed together in groups (textfigs. i6b, 25, 26, com- 

 pare the anatomical description). The tentacles are 

 16 in number, now very short, cylindrical, not pointed, 

 now conical and longer. The arrangement of the 

 tentacles in two cycles is not as distinct here as in 

 other Edwardsia-s^eciQS, at any rate not when the 

 tentacles are short. The oral disc and the actino- 

 pharynx are of usual appearance, the latter provided 

 with 8 longitudinal furrows of which the ventral one 

 is the broader and forms a weak siphonoglyphe. 

 Anatomical description. The nemathybomes 



Fig. 27. 



Textfigs. 25 — 27. Transverse sections of the scapus between 

 two mesenteries of Edivardsia pallida (figs. 25, 26) and Edward- 

 sia danica (fig. 27). ne: nemathybomes. Fig. 25 is drawn from 

 an expanded specimen, fig. 26 from a contracted, fig. 27 from a ^f |-]jg gcapus are comparatively Small and usually col- 

 rather much contracted specimen. 



lected in irregular groups; here and there a single 



nemathybome appears. In the aggregates the nemathybomes are \'ery closely packed, separated from each 

 other by a thin mesogloea-lamella. They therefore get an appearance as if they were composed of several 

 nemathybome-capsules (textfigs. 25, 26 — Carlgren 1893 PI. 2 fig.9; in the reproduced figure in my paper 

 1893 it seems as if a single nemathybome is situated right opposite to the parietal muscle; the cavity is, 

 however, an artiiicial product caused by the loosening of the ectoderm from the mesogloea.) Also in other 

 Erfwardlsja-species with scattered, not regularly arranged nemathybomes, for instance in E. vitrea, andresi, 

 danica, the nemathybomes may in transverse sections get an appearance recalling that of the nemathybo- 

 mes in E. pallida, especially if the animals are contracted, in which case the nemathybomes are of course 

 more close than when the scapus is extended. In no other species I have, however, observed nemathybomes 

 as strongly agglomerated as in E. pallida. That the nemathybomes are in reality very close we may con- 

 clude from the textfigures 25 and 16 b, the latter of which represents a piece of a compartment with the 



