CLASSIFJCA TION. 



13 



The smaller tubes are similarly "tabulate." No "septa" are 

 present. The living- animal of Millepora was first examined 

 by Professor Louis Agassiz, as the result of which he pro- 

 nounced it to be a Hydrozoon, allied to Hydradinia ; but its 

 anatomy was first thoroughly studied and worked out by Mr 

 Moseley (Phil, Trans,, vol. clxvii. p. 117, 1877), who showed 

 that it was in reality the type of a special group of Hydrozoa, 



Fig. I. — A, Portion of a mass of Millepora alc/coniis, of the natural size; B, Portion of the 

 same, cut open vertically to show the larger tabulate tubes (/, /), and the spongy coeno- 

 sarcal skeleton (c, c), enlarged; C, Small portion of the surface, enlarged to show the 

 larger and smaller openings (/', (f) inhabited by the different zooids, and the reticulated 

 calcareous tissue of the skeleton ; D, Part of a polypite, enlarged, showing two whorls of 

 knobbed tentacles. (A, B, and C are after Milne-Edwards and Haime ; D is afier 

 Martin Duncan and Major-General Nelson.) 



to which he gave the name of HydrocorallincE. According to 

 the observations of this naturalist, the colony of Mtllcpora con- 

 sists of two kinds of zooids, differing from one another in size, 

 in structure, and in function. The larger zooids — the "gastro- 

 zooids " of Mr Moseley — occupy the larger tubes of the coral- 

 lum, and have the form of short polypites, each of which pos- 

 sesses four tentacles, surrounding a central mouth, which opens 

 into the gastric cavity of the zooid (fig, 2, a). Mixed with the 

 "gastrozooids," or surrounding these in definite systems, are 

 more numerous long and slender zooids — the " dactylozooids " 

 of Mr Moseley — which carry numerous clavate tentacles (fig, 2, 



