142 



thicker and more vacuolated, and in the latter position the 

 cells appear to be directly attached to low processes of the 

 structureless lamella. Over the muscles the layer is thicker 

 with more oval nuclei (fig. 2). 



Under the mesenterial filaments the endoderm is as it were 

 concentrated to form two g'reat pads to support the filament^ 

 generally as broad or broader than the filament itself (fig, 8). 

 These are formed of granular protoplasm scattered with the 

 regular endodermic nuclei, and with small, round, deeply- 

 staining granules, appearing almost like nuclei of a second 

 order. There is here little vacuolation and no definite con- 

 tour against the coelenteron, the edge being drawn out into 

 ragged processes. In this position, though indeed they may 

 be found sparsely distributed over the whole endoderm, are a 

 few mucous cells of small size and a large number of round 

 homogeneously staining bodies of about twice the diameter 

 of the nuclei. The latter take up all stains fairly evenly, and 

 exhibit no trace of structure. When teased out they appear 

 as round refractive bodies, and are, I have no doubt, of a fatty 

 nature. In the same position at the base of the filament I have 

 also found diatoms and other algal matter inthe endoderm. 



A number of oval bodies generally occur in the endoderm 

 on each side of the upper top ends of the septa, forming 

 almost a layer (fig. 3). In a polyp with calicle 17 mm. long 

 they are only present in this position, but in smaller polyps 

 isolated ones are found anywhere over the corallum. They 

 generally do not stain, or stain very imperfectly, and appear 

 in section to have a number of pieces of a thick filament. 

 When reconstructed, a spirally coiled thick thread is found 

 (fig. g). The various coils, about 12 to 15, are in contact, and 

 extend diagonally around the whole. The appe:irance ap- 

 proaches that of the mesenterial nematocysts of Cocnopsamviia 

 \loc. cit.y p. 370), but with enormously swollen threads and no 

 discharging apparatus. Most are in the same condition as 

 in the figures, but I have found a few with as yet no thread 

 developed. Some have no nuclei, but where present they are 

 oval and densely granular. There are no indications of any 

 having been ejected, nor of any possibility of ejection. There 

 can, however, be no doubt, but that they are nematocysts,. 

 perhaps rudimentary or reduced. As such their position, 

 especially on the upper free edges of the septa, is probably 

 not devoid of morphological significance. 



Grenerative Organs. — In the young stage the testes are 

 composed of small cell masses, forming follicles in the 

 structureless lamella. Later, as described by Hickson in 

 Alcyonium,*each follicle consists of a dense mass of granular 

 nuclei surrounding a small open central coagulum. 



* Quart. Jour. Micr. Sci., vol. 37, p. 343 (1895). 



