ACTINIARIA 



6i 



Textfigs. 73—75- 



Milne-Edwardsia loveni. 



Fig. 7,5. Transverse section of pennon in 



the upper part of the reproductive tract. 



Kig. 74. Transverse section of a portion 



of capitulum with a parietal muscle. 



I''ig. 75. Transverse section of a portion 



of the capitulum n : neraatocysts. 



ing to the insertions of the mesenteries. The actinopharynx is short, with 8 longitudinal ridges and as many 

 longitudinal furrows. The siphonoglyphe is ventral, indistinct, about twice the breadth of the other longi- 

 tudinal furrows in the actinopharynx. 



Anatomical description: The scapus-ectoderm is high, especially in the proximal part and on 

 the ridges, and several times thicker than the mesogloea; also in the distal parts it is higher than the meso- 

 gloea. The nematocysts are few in number between the ridges, on these latter very numerous but scattered 

 and do not seem to form any such groups as in M. carnea. They are most frequently a Uttle curved, with rather 

 indistinct basal part to the spiral thread which follows the whole length of the capsules, and they are 36 

 — 48 X 6// in size. 

 Further down 

 there are also 

 smaller capsules, 

 about 24 fjL long. 

 The cuticle of the 

 scapus is very 

 thick, the outer 

 part of it is rather 

 easily loosened 

 from the under- 

 lying, thinner 

 substitutive-cu- 



ticle, and is a little incrustated. The ectoderm of the capitulum is in the ridges high, with numerous nematocysts, 

 22 — 30 // long and 4// broad; in the furrows lower, with very few nematocysts (textfig. 75). The mesogloea 

 is much thicker on the ridges than in the furrows, where it is rather thin. The endodermal circular muscles 

 are weak and form no sphincter. The ectoderm of the tentacles contains ver>' numerous nematocysts, about 

 22 X 4 /.( in size, and spirocysts of variable length; the largest are of about the same size as the nematocysts. 

 The ectoderm of the actinopharynx is high on the ridges and many times higher than the mesogloea, with 

 comparatively rare nematocysts, partly smaller, 17 — ig^yz long, partly larger, 24 — 29 X 3 /.i, and numerous 

 gland-cells. The nematocysts are mainly arranged on the ridges; in the furrows they are very few. The 

 siphonoglyphe is only a httle differentiated from the other part af the actinopharynx. The mesogloea is 

 a little thickened on the insertions of the mesenteries and ends in a thin lamella. 



The weak, imperfect mesenteries are rather thick. The longitudinal pennons of the 8 perfect mesen- 

 teries are in the reproductive region provided with 20 to 30 folds wliich are of about equal height and rather 

 much ramificated (textfig. y^,). The outer lamellar part of the mesenteries issues very close by the outer 

 edge of the pennons. The parietal muscles (textfigs. 74, 75) are well developed, with thin folds of a charac- 

 teristic appearance. They appear fan-shaped on transverse-sections; the lamellar part of the mesenteries 

 issues from the base of the fan. The cihated streaks are present, though not long. The animal is dioecious. 

 Biology : The animals live in dead coral-branches of Lophohelia and Paragorgia, sometimes on 



Fig- 73 



.^ 



