64 ZOOLOGY. 
about like the Aurelia by alternate contractions and expan- 
sions of the umbrella. We will now enter into a more com- 
plete account of this group based on Clark’s characteriza- 
tion. The disk is more or less octagonal or circular, um- 
brella, funnel or urn-shaped, the end opposite the mouth 
ending in a pedicel, by which it is attached temporarily to 
sea-weeds, The mouth is square, and between the ectoderm 
and endoderm is a jelly-like layer constituting the musculo- 
gelatiniform layer (mesoderm) much as in Aurelia. This 
layer extends into the tentacles and marginal anchors, as 
well as into the pedicel. The cavity of the disk is divided into 
four quadrant chambers, separated by as many partitions, 
which extend from the mouth into the lobes nearly to the 
margin between the tentacles. The latter are arranged in 
eight groups or tufts just within the margin of the disk, at 
eight points, which alternate with the four partitions and 
the four corners of the mouth. The tentacles are hollow, 
opening into the radial canals of the general cavity of the 
body, and end in a globular or spheroidal expansion, serv- 
ing as an organ of touch or prehension. In some forms, as 
Haticlystus auricula Clark, marginal anchors are situated 
at eight points, exactly opposite the four partitions and the 
four corners of the mouth ; they are originally tentaculiform, 
but in adult life form organs by which they adhere to or 
pull themselves from place to place. The sexes are distinct, 
the reproductive glands having the same position in each 
sex. Nothing is absolutely known of the mode of growth 
of these animals, but development is supposed to be direct. 
Our common Lucernarian is Haliclystus auricula Clark. 
Its umbrella-shaped disk is an inch in diameter ; including 
the tentacles, an inch and a half; the pedicel half an inch 
long. It ranges from Cape Cod to Greenland and south- 
ward to the coast of England, and may be found on eel- 
grass between tide-marks. 
According to A. Meyer, the end of the stalk when cut off 
produced a new disk, and even pieces cut off between them 
became complete Lucernarie, evincing the extraordinary 
powers of reproduction in these interesting jelly-fish. 
Coming now to the true Discophora, jelly-fish, sea- 
