POPULAR SCIENCE REVIEW. 
224: 
table aspect combines with an animal structure. Its scientific 
equivalent is found in the term Coelenterata, the name which 
the able German physiologists Frey and Leuckart have be- 
stowed on the sub-kingdom, under which they have ranged a 
portion of the miscellaneous contents of Cuvier’s Radiate divi- 
sion. The establishment of this new province is one of the 
later results of zoological research ; and though not universally 
recognised, it may be said to have made good its place amongst 
the primary departments of the animal kingdom. 
The Coelenterates are distributed under two principal groups, 
the Hydrozoa and the Actinozoa ; the former including the 
Hydra and its immediate kindred, the Hydroid Zoophytes, to 
which the tribe belongs that is the subject of this paper ; the 
free-floating oceanic forms, of which the Velella and the Portu- 
guese man-of-war {Physalia') are familiar examples ; and the 
large “blubbers ” or jelly-fish that often crowd the surface of 
the sea or strew the beech in autumn : the latter embracing the 
sea-anemones and their coral-making relatives, &c. 
We propose to deal at present with that section of the Hy- 
droid Coelenterates in which' most of the exquisite corallines 
that are likely to fall in the way of our readers during their 
visits to the sea-side find a place. Between the plant and these 
plant-like beings there is not merely a close resemblance in 
external form ; there is also a striking analogy in some respects 
between the life of the two. The Hydroid embryo, driven 
through the water by the action of a thousand invisible paddles, 
comes to rest at last on some point of the rock, on the shell of some 
mollusc, or on the surface of some broad Laminarian frond. 
There it attaches itself, discarding its locomotive appendages, and 
enters upon a course of development which reminds us forcibly 
of the mode of growth in the vegetable kingdom. It first 
expands into a circular disc, from the centre of which rises an 
upright stem, the whole structure being now clothed with a 
delicate horn-like investment. (Plate XLV. fig. 4.) The 
upper extremity of the stem enlarges, and is gradually developed 
into ahydraform zooid orpolypite, which may be regarded as the 
equivalent of the leaf-bud. After a time the ascending stem 
puts forth other buds, which become polypites,or branches bearing 
them, and these branches give off their branchlets, and the po- 
lyj)ites continue to multiply like leaves upon the tree; and this 
vegetative process proceeds until the simple primary shoot has 
expanded into the lovely arl)orescent structure which the sea has 
torn from its attachment and flung at your feet. At the same 
time other changes liave been going on. The disc by which 
the niiscent zoophyte is fixed in its place sends out thread-like 
prolongations, wliich creep over the surface that supports it, 
like delicate rootlets, and from the net-work thus formed new 
shoots arise by a process of repeated budding, until at last a 
