THE PYCNOGONIDS. 3 



in turn swished rapidly backward and forward in a dish con- 

 taining a small amount of water, so that the Pycnogonids 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 bunches strung along 

 on the ovigerous legs of the male: the bunches are white and 

 very conspicuous against the purple color of the adult. Tany- 

 stylum has smaller bunches of eggs, with the individual eggs 

 larger than the former, and the masses are carried so that they 

 form a circle of clusters held against the ventral side of the male. 



The adults with eggs were put into alcoholic picro-sulphuric 

 acid for several hours and then gradually carried through different 

 grades of alcohol of increasing strength. Other methods of 

 hardening gave far less satisfactory results, i. e. boiling water or 

 Flemming's solution. 



To prepare the eggs and embryos for study they were passed 

 through absolute alcohol (one hour), turpentine (2-4 hours), soft 

 paraffine (one hour), hard paraffme (1-2 hours). They were cut 

 in paraffine, and fixed to the slide with albumen fixative ; then 

 back again through turpentine, absolute alcohol, 95 percent, 80 per 

 cent, 70 per cent alcohols to Kleinenberg's hematoxylin, where 

 they remain for a very long time (12-48 hours) ; then washed 

 fifteen minutes in acid alcohol and up again through the alcohols 

 to turpentine and into balsam. In Pallene each egg was in 

 many cases pricked with a very sharp needle before going into 

 absolute alcohol. It is necessary to do this under a dissecting 

 microscope. By these methods very excellent results were often 

 obtained and, after many failures of other methods, was found to 

 be the only satisfactory one. In Pallene the larger size of the 

 egg makes a study of the earlier stages much easier, but the other 

 genera have a much simpler development, and it seems better to 

 give first an account of these. 



To Prof. W. K. Brooks I am greatly indebted for help and 

 suggestions during the work. 



