LIFE HISTORY OF ANAPHIA PETIOLATA. 53 
in the tow-nettings from outside the Breakwater, Plymouth, extended 
flat on the top of the bell of an Obelia medusa, and clinging to it. So 
beautifully was it balanced that the medusa could swim perfectly, although 
weighted by the Pycnogonid. 
If medusee and Pyenogonids are left together in a vessel, e.g. Anaphia 
petiolata or Endeis spinosus, it is nearly always found that the Pyenogonids 
are attracted towards the meduse and cling to them. The only movement 
made by the young larvee when taken from the medusz is a strong waving 
of the chelz, and if these come in contact with a medusa they cling tightly 
to it. 
Fre. 1.—Larval stages of Anaphia petiolatus (Kroyer). 60. A. Youngest stage in Obelia 
medusa; B. Later stage; C. Still later stage, the legs having been separated 
with needles. I-VI. The appendages. Ventral view. 
The larva at all stages is of a pale yellow colour, and has its legs so 
folded that they pack into the smallest possible space. As many as four 
were found in one medusa, but usually there is only one. It grows rapidly, 
and the body elongates considerably together with a great lengthening 
. of the legs. In the youngest stage found (Fig. 1, A) the legs (IV-VI) 
were short, roundish stumps, the alimentary canal extending into them 
and well into the chele. The chele were powerfully developed with 
strong claws; remains of the second and third larval appendages were 
seen as small hair-like protuberances. These, however, are often very 
difficult to see, and the drawing shows an exceptionally clear specimen. 
These appendages, although dwindling, persist until the larva has grown 
to nearly twice the size ; in this differing from Dogiel’s observations, who 
describes them as disappearing almost at once. 
