ACTINIARIA 



193 



and, as Danielssen states, of an almost triangular form. 

 In their uppermost part they are provided with distinct 

 gonidial tubercles. 



Anatomical description. The pedal disc has a 

 rather thick cuticle. The ectoderm of the column is somewhat 

 low and contains rather numerous nematocysts 22 24 X 

 about 4 // in size, and numerous mucus-cells. The meso- 

 gloea is in the proximal part thin or of ordinary thickness, 

 corresponding to the different state of contraction, but 

 swells out in the region of the sphincter and there forms 

 a thick layer; it contains small protoplasma-poor cells. 

 The endodermal circular muscles are weak, the mesogloeal 

 sphincter, on the other hand, is very strong and juts out, 

 during certain states of contraction, as a strong thickening 

 towards the ectoderm, about as the sphincter of Tealidium 

 cingulatum (Hertwig 1882 PI. 6 fig. 2). In the upper 

 part and in the greater part of its length it occupies almost 

 the whole breadth of the mesogloea, proximally it decreases 

 rapidly and takes up only the inner 

 part of the mesogloea. The mus- 

 cle meshes are very small, in certain 

 parts very close, in other parts se- 

 parated by larger lamellae of the 

 mesogloea. Any distinct stratifica- 

 tion of the sphincter is, however, 

 not to be seen (textfig. 183). 



The ectoderm of the ten- 

 tacles is very high and contains very 

 numerous spirocysts of very vari- 

 able size, unto 53 x 4 6 p ; on the 

 other hand, the typical nematocysts 

 are very sparse and 26 -29 X 4 



Fig. 183 



Fig. 184 



in size. In the swollen basal part, F 'g- 18 5 Fi S- l86 



Textfigs. 183 186. Anthosaclis jan tnayeni. 

 On the outside of the Outermost Fig. 183: Transverse section of sphincter. Fig. 184: Transverse section of an outer- 



tentacles, there is a specific stinging raost tentade ' at the basis showing the battery of nemat c >' sts <"> Fi s s - 185-186: 



Transverse section of an inner tentacle fig. 185 at the abaxiale, and fig. 186 at the 

 organ developed (textfig. 1 84) , which adaxiale side. 



I have also observed in Tealidium jungerseni. This battery contains very numerous, closely packed nemato- 

 cysts (fig. 184 ) of considerable size (74 93x12 13//), which are, however, smaller than those of Tea- 



Thc Ingolf-Expedition. V. 9, 



