ACTINIARIA 



73 



scapus is quite smooth. The scapus is in fact provided with scattered "//afcaw/>a-papillae" to which small 

 grains are sometimes attached in the proximal parts of the scapus (textfig. 87, PI. i, figs. 8, 9). The capitulum is 

 polygonal and has 8 rather elevated longitudinal ridges between the insertions of the mesenteries. The tentacles 

 of Lecythia are (according to Sars) 20, 25 26 in number, those of carnea, according to Appellof, some 20 

 to some 30. I have observed 24 28 tentacles myself. The inner tentacles are longer than the outer ones, 

 all short and of about the length of the capitulum, conical and hexamerously arranged in at least 3 cycles. 

 Appellof says that there are only 2 cycles of tentacles present. The oral disc is inconsiderable. The actino- 

 pharynx is short, with 8 longitudinal furrows and the same number of longitudinal ridges. A feebly developed 

 ventral siphonoglyphe seems to be present. 



Anatomical description: The physa is devoid of a periderm. The ectoderm contains numerous 

 nematocysts, 8 15 // long. The scapus-ectoderm is high and covered with a thin periderm. Its nematocysts 

 are numerous and of two dimensions, partly comparatively broad 17 22 X 3,5 4//, partly smaller, thin- 

 ner and about 8 12 // long. The mesogloea is of about the thickness 

 of the ectoderm or thinner and almost homogeneous. The endoderm 

 is a little lower than the ectoderm and contains numerous nemato- 

 cysts (text fig. 89, 92 ), 34 38 x 5 n in size and often a little cur- 

 ved; these endodermal nematocysts make a characteristic feature of 

 this species. I have observed such capsules also in the endoderm of 

 the tentacles and of the actinopharynx. (Their size is 36 43 X 5 //). 

 The capitular ectoderm is high and provided with nematocysts which 

 are smaller in the proximal parts (10 14 long), in the distal part, 



Fig. 87. Paraedwardsia sarsii. Arrangement 



on the other hand, unto twice that length. In the furrows they are O f the -Halcampa-papittae" between two 

 ... ,. 11-r it. mesenteries, pm: parietal muscles. 



sparse, on the ridges numerous. According to Appellot there are 



nerve-cells and nerve-fibrillae in the capitular ectoderm. The capitular ridges arise from the thickenings 

 of the mesogloea. The ectoderm of the tentacles contains rather sparse nematocysts, 19 22 X 2 ft in size, 

 and numerous spirocysts unto 28 X 5 p in size. The ectoderm of the actinopharynx is high with scattered 

 typical nematocysts partly smaller 14 22 X 1,5 2 //, partly larger, 24 29 X 2,5 3,5 //. Besides these, 

 there are also nematocysts with distinct basal part to the spiral thread and somewhat broad in the basal 

 end. Their size is 22 24 X 3,5 5 n- The ectoderm of the siphonoglyphe is only a little differentiated from 

 the other ectoderm of the actinopharynx, but it is provided with longer cilia than this part. Appellof has 

 not found any differentiation of the actinopharynx. 



The weak imperfect mesenteries in the most distal part are rather well developed. The longitudinal 

 muscle-pennons of the 8 perfect " Edwardsia-mesenteries" are in the reproductive region provided with 15 

 20 folds (textfig. 88) which are a little ramificated, mainly in the outer part. The inner folds of the pen- 

 non are considerably lower than the outer ones, and the pennon itself, on transverse-sections, rather elon- 

 gated in the reproductive region (textfig. 88). The lamellar outer parts of the mesenteries are attached to 

 the pennon in its outer part. In the endoderm of the mesenteries large nematocysts of the same structure 



The Ingolf Expedition. V. 9. 



