IO8 W. C. ALLEE. 



time they are collected in separate bottles placed in a larger dish 

 of running- sea-water to prevent fragmentation. We usually 

 study the swimming motions of Ophioderma. 1 



Living representatives of all available echinoderms are kept in 

 aquaria in the center of the laboratory. Some of these contain 

 starfish and mussels and give the starfish an opportunity to demon- 

 strate their feeding methods. Thyone are allowed to bury them- 

 selves in muck and show their usual feeding reactions and 

 method of respiration. 



The last half day is spent on a dissection of narcotized Thyone. 

 For this work freshly collected specimens are best. These are in- 

 jected about an hour before use with about 15 cc. of chloretone 

 solution recently saturated when hot. After a short time the ten- 

 tacles can be forced out by gentle manipulation and, the narcotiza- 

 tion holds during the dissection in sea water. It is essential that 

 the chloretone solution should be as strong as possible. There is 

 a great difference between these narcotized animals and the usual 

 formalin faded specimens. 



Annelida. Three days, lecture and laboratory. Nereis virens 

 living, preserved, or narcotized in alcoholic sea water, forms the 

 entering wedge for this group. Cleared transverse sections of 

 whole segments are also used to show general relations and 

 especially the parapodia. Arcnicola, freshly narcotized, are dis- 

 sected for the blood system and for the nephridia, following di- 

 rections based on Ashworth's monograph. 2 Sometimes we dis- 

 sect Amphitritc (see appendix III.) and a large collection of 

 other worms is present in the laboratory. Usually Lcpidonotus 

 is studied for external features, and of recent years a half day has 

 been spent in classifying local annelids, using Pratt's key. Phos- 

 phorescence can be successfully demonstrated in Chcstopterus by 

 taking the animals to the dark room at night, and the class col- 

 lects swarming Nereis limbata when moon and weather permit. 

 The last half day is normally spent in a dissection of the common 

 sipunculid', Phase olosoma, freshly narcotized in alcoholic sea 

 water. 



1 Grave, Caswell, " Ophiura (Ophioderma) brevispina," Mem. Biol. Lab. 

 Johns Hopkins Univ., 4, 1900. 



2 Ashworth, J. H., Liverpool Marine Biology Committee Memoirs, XL, 1904. 



