94 SYNOPTIC COLLECTION. 



bundles of fibers that arise from the radiating vessels, 

 the latter being the continuations of the body cavities of 

 the zoons. Besides the longitudinal muscles the circular 

 muscles are shown. Fig. 9 is a vertical section through 

 the decalcified superficial fleshy lamina which was living 

 before decalcification began ; the ectoderm is distinctly 

 seen, also the retracted gastrozooids on the right (one 

 of the four tentacles is not drawn), and the retracted 

 dactylozooid on the left. The network of fleshy tubes is 

 finely seen and where these are cut the dark pigment cells 

 of the endoderm are visible. The limy network of the 

 skeleton is shown by the open spaces between the fleshy 

 tubes. Figs. 10-15 represent the skeleton. Fig. 10 is 

 a fragment magnified two diameters, showing the branch- 

 ing form and the pores scattered over the surface. Fig. 

 1 1 is a drawing of a thin section of the skeleton showing 

 its fibro-crystalline structure. Fig. 12 is a complete group 

 of pores consisting of one central gastrozooid pore and 

 eight dactylozooid pores, greatly enlarged. The structure 

 is brought out clearly by figs. 13-15. Fig. 13 is a verti- 

 cal section of the skeleton. The large gastrozooid pore 

 is seen in the middle and the floor that separated the last 

 formed living chamber from those below which are dead. 

 The branches of the canal system are plainly shown. Fig. 

 14 is a horizontal section cut parallel to the outer surface, 

 showing part of a group and the system of canals. In 

 fig. 15 the pores and canals have become filled with black 

 foreign matter making a cast of the canal system of the 

 flesh or coenosarc. Nothing was known of the generative 

 organs of Millepora till 1884, when Quelch l found among 

 the young branchlets of the hard skeleton large ampulla- 

 like cavities similar to those that had previously been 

 observed in a related group, the Stylasteridae. These 

 cavities contained gonophores and in the specimen exam- 

 ined only the male elements, spermatozoa, were found. 



1 Nature, XXX, 1884, p. 539. 



