Stkphknhon — Certain Aetiniaria collected off Ireland. 15.0 



we hardly know at present. When one has sketched a dozen or so of them 

 from one species and a dozen from another, a general difference in aspect 

 is sometimes noticeable between the two selections. But it is too indefinite to 

 state very clearly, and probably their appearance would vary according to 

 the condition of the specimen (whether it had recently had a meal or not, &c.), 

 and the action of the reagents used. I have selected a number of typical 

 examples, and included them in PL XVI, to show the extent of their variation. 

 They are probably nutritive amoeboid cells with a secondary nervous function 

 (as I have suggested before — 48, p. 3.) The granular ones typical, for instance, 

 of Chondrodactis pulchra, strongly suggest granular food-contents (figs. 13-15); 

 those such as are illustrated in figs. 6, 8, 9, possibly contain liquid food in 

 vacuoles. The fact that these cells are often formed into strings or networks 

 i tigs. 19, 21, 14) suggests that they communicate with each other and may 

 have a secondarily nervous function. They vary in number in different 

 species to some extent, and are more numerous in some parts of the body 

 than in others, in the same animal. Their forms are almost infinitely 

 variable — unipolar, bipolar, stellate, amoeboid, &c. ; they may be granular, 

 mealy, clear, dim, distinct, or indistinct in appearance. Sometimes they lie 

 in clear spaces in the mesogloea. Sometimes they seem to consist of practically 

 nothing but a nucleus. In some cases one may catch them in the act, 

 apparently, of migrating into or out of the ectoderm or endoderm into the 

 mesogloea —which one would expect them to do if they are carrying nourish- 

 ment. (PI. XVI, figs. 24, 25, 26.) The matrix of the mesogloea is variable, 

 from being fibrous in appearance to being practically homogeneous, but I am 

 doubtful whether that is of much importance; it must be a good deal affected 

 by reagents sometimes. 



BIBLIOGRAPHY. 



1. Andres, A.— LeAttinie. Mem. E. Acad. Lincei, Rome. Ser. 3. Vol. xiv, 



1883, p. 211. 



2. Annandale, N.— Coelenterates. Fauna of the Chilka Lake, No. 1. Mem. 



Ind. Mus. Vol. v, 1910. p. Go. 



3. Boukne, G. C— Anthozoa. Lankester's Treatise on Zoology. Part II. 



London, 1900. 



4. Boukne, G. C— A description of five new species of Edwardsia, Quatr., 



from New Guinea, with an Account of the Order of Succession 

 of the Micro-mesenteries and Tentacles in the Edwardsiae. 

 Journ. Linn. Soc. Vol. xxxii, ZooL, 191G, p. 513. 



