76 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY. 



adjacent pairs, the interseptal (is). Some slight direct communi- 

 cation with the exterior, is usually provided for these chambers, by 

 a pore (tp) at the tip of each tentacle, which are simply hollow 

 outgrowths of the peristome. Intercommunication is also allowed by 

 the presence of one, sometimes of two pores piercing the mesenteric 

 walls just beneath the peristome (ip and op). 



Examining a transverse section with the microscope, we can 

 resolve the wall of the body and of the oesophagus (a mere down- 

 growth of the mouth disc), into three well differentiated layers. The 

 most obvious is the middle one — mesoglsea or supporting' lamina — 

 consisting of a thick layer of a clear, fibrillated tissue, approaching 

 somewhat the texture of tendon, denoted in Figs. 1 and 2 by black 

 bands and lines. Outer to this is the ectoderm or epidermal layer, 

 containing in certain regions, glands and stinging cells or nematocysts. 

 This is the seat of what poorly developed nerve elements there are 

 in these animals. 



On the inner side of the mesoglsea, is the thin but important 

 layer of the endoderm, lining the entire body cavity in all its 

 chambers with a coating of ciliated cells, which give off strong 

 muscle fibres on the side in contact with the mesoglsea. The 

 principal functions of the endoderm are those of digestion and 

 the provision of muscular movement. 



Most anemones have great powers of contraction, being able in 

 many cases to reduce their bulk to less than one-seventh of that 

 when fully expanded. The principal muscles employed are strong 

 longitudinal ones running in the ridged surface of each mesentery. 

 The supporting lamina is much folded at this point, forming in 

 section, a beautiful arborescent pattern, and along these multiplied 

 faces run from base to peristome, great numbers of muscle fibres, 

 whose duty it is to pull down the tentacles and mouth-disc, and so 

 shorten and retract the animal. On the other face of the mesen- 

 teries the muscle fibres run transversely ; so that we may describe 

 the disposition of the mesenteric muscles as usually longitudinal on the 

 intraseptal surface, and as transverse on the interseptal. The latter 

 towards the base of each mesentery alter their course so as to run 

 obliquely from the wall downwards to the base — the parieto-basilar 

 muscle (pom). In the walls, the peristome, the oesophagus, and 

 usually also in the base, the muscular processes of the endoderm cells 

 are arranged in a circular direction. 



No animal is more ravenous. Crabs, molluscs, and small fishes 

 wandering incautiously close, are entwined and pulled inwards by the 

 long tentacles, the while that cruel stinging cells are conveying into 

 the poor quivering body, a poisonous, numbing juice through innu- 

 merable thread-like barbs. Still struggling, the prey is passed 



