1891.] Microscopy. 397 
MICROSCOPY. ! 
The Pycnogonids.?—Three genera of Pycnogonids, each with a 
single species, are to be found at Wood’s Holl,—viz., Pallene empusa, 
Phoxichilidium maxillare Smith (Anoplodactylus lentus Wilson), and 
Tanystylum orbiculare. During July, August, and September these 
are found with eggs. Pallene inhabits the hydroids (Tubularia, 
Pennaria) on the piles of the wharves, and is also common on the red 
sea-weeds below low-tide mark. The hydroids or sea-weeds as soon 
as collected were bfought into the laboratory and worked over piece 
by piece. Each bunch was in turn swished rapidly backward and for- 
ward in a dish containing a small amount of water, so that the Pycnog- 
onids were shaken loose and could be easily picked out. The other 
genera were more easily found, and on separating the masses of 
hydroids, etc., could be readily seen clinging to the stems. The males 
of Pallene carry on each pair of ovigerous legs a small bunch of eggs. 
Each bunch contains from one or two to fifteen or twenty eggs. The 
eggs of Phoxichilidium and Tanystylum are individually much smaller 
than the last, but are very numerous, so that the bunches are much 
larger, especially so in the former. Phoxichilidium carries several 
lunches strung along on the ovigerous legs; the bunches are white, 
and very conspicuous against the purple color of the adult. Tanysty- 
lum has smaller bunches of eggs, with the individual eggs larger than 
the former, and the masses are carriéd so that they form a circle of 
clusters held against the ventral side. 
The adults with eggs were put into alcoholic picro-sulphuric acid for 
several hours, and then gradually carried through different grades of 
alcohol. Other methods of hardening gave far less satisfactory results, 
—#.e., boiling water or Flemming’s solution. 
To prepare the eggs and embryos for study they were passed through 
absolute alcohol (one hour), turpentine (two to four hours), soft 
paraffine (one hour), hard paraffine (one to two hours). They were 
cut in paraffine, and fixed to the slide with albumen fixative; then 
back again through turpentine, alsolute alcohol, ninety-five per cent., 
eighty per cent., seventy per cent. alcohol to Kleinenberg’s hematoxy- 
lin, where they were left for a very long time (twelve to forty-eight 
hours); then washed fifteen minutes in acid alcohol, and up again 
1 Edited by C.O. Whitman, Clark University, Worcester, Mass. 
2 
T. H. Morgan. Studies Biol. Lab., V., 1, 1891, pp. 2, 3. 
