58 ZOOLOGY. 
ramifications. The whole canal system is connected to- 
gether by a freely anastomosing mesh-work of smaller ves- 
sels, and communicates freely by numerous offsets with the 
cavities of the calicles.’? As the animals increase in num- 
bers and die, the coral stock increases in size, the layer con- 
taining the living animals forming a thin film only, the 
bottom of the little cups or pores forming a table or plat- 
form, whence the term Tabulata, originally applied to this 
group, the old calicles being divided by a series of trans- 
verse plates or lamina, separating them into series of cham- 
bers. Moseley shows that the corallum of Millepora is dis- 
tinguished from all other coralla by its systems of canals 
branching in an arborescent manner, while the tabulate 
structure occurs in certain Aleyonuria, Zoantharia, and in 
other Hydroida; hence the group Tabuwlata, as previously 
stated by Verrill, is an artificial one. 
The animals of the Millepora are of two kinds ; those in- 
habiting the central cup or pore are short, thick zooids, 
with a mouth and four tentacles, and only half a milli- 
metre in height ; those in the smaller pores are longer and 
slenderer, about one and a half millimetres in height, with 
from usually five to twenty tentacles, situated at irregular in- 
tervals from the base to the summit of the body. The body 
cavities of the zooids end in blind saes at the bottom of the 
cup, but are continuous beyond with the canals of the hy- 
drophyton, the latter being defined by Allman as forming 
in the Hydroids ‘‘ the common basis by which the several 
zooids of the colony are kept in union with one another.” 
As we know nothing of the mode of reproduction of Mille- 
pora, we must leave it for the present near Hydractinia, to 
which the adult animals are nearest related. Moseley also 
discovered that Stylaster, a beautiful pink coral which grows 
at Tahiti, with the Millepora, is in reality a Hydroid, und 
not a true coral polyp, as has always been supposed. That, 
finally, Millepora is a true Hydroid is proved, Moseley thinks, 
by the peculiar structure of the hydrophyton, the forms of 
the zooids, the absence of all trace of mesenteries, the ap- 
parent septa present in the tentacles, and by the presence 
of thread-cells of the form peculiar to the Hydroza. The 
