ACTINIARIA 



191 



longitudinal furrows and 2 siphonoglyphes. Few (6, 8 to 12) perfect pairs of mesenteries. L,ongitudinal 

 muscles of the mesenteries comparatively weak. Reproductive organs present, at least on all stronger mesen- 

 teries. 



Danielssen (1900) declares that the genus is provided with cinclides, and refers it to the family 

 Sagartiidae. According to my examination of the tj^pe-specimen, no such cinclides are present (compare 

 below!). The genus is besides a typical Paractiidae and easily recognizable on the structure of the tentacles, 

 for one thing. Their longitudinal muscles are namely at the base much weaker on the outside than on the 

 inside, and ectodermal to meso-ectodermal, perhaps sometimes ecto-mesogloeal (in A. excavata (R. Hertw.)). 

 Furthermore, outer tentacles are at the base on the outside provided with a strong battery of very long and 

 broad nematocysts of a characteristic type, an arrangement, observed by myself only in the genera Anthosactis 

 and Tealidium. Probably this battery has the same function as the acrorhagi. 



To this genus I have before (1912 p. 43) placed Paractis excavata, described by R. Hertwig (1882), 

 for which species Verrill (1899 p. 144) has proposed the name Alloactis excavata. The whole habitus and the 

 anatomical structure of this species indicate that we have to do with a species of Anthosactis. It remains, 

 however, to be ascertained, if the outer tentacles are provided with the above named particular nematocyst 

 batteries. 



Anthosactis jan mayeni Dan. 



PI. 2. Figs. 6 — 7. 



Anthosactis jan mayeni n. sp. Danielssen 1890 p. 24, PI. 2 fig. i, PI. 10 fig. r. 

 — — — Dan. Carlgren 1912 p. 21, 1916 p. i. 



Diagnosis: Pedal disc with a cuticle. Column with more or less distinct longitudinal furrows. 

 Tentacles conical, longitudinally sulcated in contracted state, not hamiform, in 4 or 5 octamerously arranged 

 cycles, of which the first and the second are very close. Inner tentacles thicker and longer than outer ones. 

 Outer tentacles a little swollen at the base. lyongitudinal muscles on the outside almost exclusively ectodermal 

 and not as strong as on the inside, where they are even meso-ectodermal. Oral disc with weak radial ridges 

 and weak, partly mesogloeal muscles. Actinopharynx with few, longitudinal ridges. Pairs of mesenteries 

 arranged octamerously (8 + 8 -f- 16 -f an imperfect fourth cycle in large specimens). Only 8 pairs perfect. 

 Small oral stomata, no marginal stomata. Parietobasilar muscles broad but only a little folded, about two 

 thirds as long as the mesenteries. Ectoderm of the column with nematocysts 22 — 24 X about 4 // (seldom 

 29 X 6 ;u) in size. Ectoderm of the tentacles with extraordinarily numerous spirocysts of variable size, unto 

 53x4 — (3 fi, and with very sparse nematocysts (26 — 29 X 4(5) fi). Stinging capsules in the battery of the 

 outer tentacles very numerous 74 — 93 X 12 — 13 ^. Typical nematocysts in the ectoderm of the actinopha- 

 rynx few 22 X3,5 (I, its nematocysts with distinct basal part to the spiral thread very numerous, 26 — 34 X 

 about 5 fi. 



Colour of the column pale reddish- white, but on account of the red oesophagus it acquires a reddish 

 tinge, while the uppermost margin is white. Tentacles rose-red, shading off a little into yellow. Oral disc 

 darker yellowish-red with paler yellowish-white rays, radiating from the mouth towards the middle of the 



