64 



ACTINIARIA 



Fig. 76. 



Fig. 77. 



Anatomical description: The ectoderm of the scapus is high, thicker than the mesogloea and 

 contains nematocysts, 29 — 34 (37) X 7 — 8 /i in size, often somewhat curved, and large, very numerous 

 gland-ceUs. The nematocysts are packed together in greater and smaller groups; there are, however, also 

 a few nematocysts between the groups. The ectoderm of the capitulum is in the longitudinal ridges very 

 high (textfig. 79) , a Uttle thicker than the mesogloea, but in the furrows thinner. In the ectoderm of the ridges 

 there are numerous nematocysts, 26 — 46 ^ long and almost 7 fi broad, often a little curved, while the ecto- 

 derm of the furrows does not contain any such. The mesogloea is thickened in the ridges. The ectoderm of 



the tentacles is provided with 

 very numerous, smaller nema- 

 tocysts (18 — 24 X 5 /i) and some 

 few, a little larger (27 X 7 /i). 

 The spirocysts are of variable 

 size, the largest about 24 ji long. 

 The ectoderm of the actino- 

 / pharynx is high in the ridges 

 as on the capitulum; in the 

 furrows thinner and provided 

 Pig yg with numerous, granulate 



M ilne-Edivardsia carnea.Vig. 76 gland-cells. Mainly in the rid- 



Transverse section through a 



portion of scapus in the repro- S^s typical nematocysts are 



ductive tract. Figs. 77—78- found (17— 20 X 3 //) and some 



Transverse sections of pennons 



in the reproductive tract. Fig. such with distinct basal part 

 79. Transverse section of a por- ^^ ^^^ -^^ ^-^^^^^ ^^^^ ^ ^^^1^ 

 tion of the capitulum, n : ne- 

 matocysts, me : mesentery. broader in the basal end (22 — 



29x5,^. In the probably differentiated siphonogljrphe the gland-cells and spirocysts are few in numbers. 



The imperfect mesenteries in the most distal part of the body are considerably weaker than in 

 M. loveni. The perfect, well-developed mesenteries are as usual in the Edwardsiidae 8 in number, in a spec- 

 imen I have, however, found only 7 stronger mesenteries and 7 ridges in the actinopharynx (compare the 

 similar discovery by lyevander in " Edwardsia carnea" = Paraedwardsia sarsii?). The folds of the longi- 

 tudinal pennons are comparatively few in the reproductive region, ordinarily liigh and only a little rami- 

 ficated, commonly 12 in number, sometimes many, but never more than 20. The lamellar outer part of the 

 mesenteries issues not far from the outer edge of the pennons (textfigs. 77, 78). The parietal muscles (text- 

 fig. 76) are in the capitular region very strong, in transverse-sections triangular or rather fan-shaped, they 

 recall those of M. loveni, though they are not as richly folded ; in the reproductive region they are a Uttle 

 weaker. Their expansion on the column is not considerable in the most distal part, in the reproductive 

 organs they are a little more expanded, though only as far as to half their breadth. The ciliated streaks-are 

 well developed, just as well as the intermediate streaks. The animal is dioecious. 



Biology : According to my observations this species as well as M. loveni are not sensitive to the 



