450 ^^' '"^ NICKKRSON, 



iron - sulphate haematoxylin of Heidenhain is to be preferred to 

 either. None of the conimou carmine or cochineal stains which I 

 tried were satisfactory, though Mayer's HCl-carmine is to be pre- 

 ferred to any of the others. Several of the commoner aniline dyes 

 also failed to give useful results. 



I had hoped that by feeding some of the larval worms to fishes 

 I might be able to learn something of the later life history of this 

 Trematode. The amount of material which I obtained was so small 

 however that I could hardly ati'ord to use any considerable number 

 for such experiments. 



I fed several of them, a part still in the cysts and others freed 

 from their cysts, to two fishes — one a small flounder and the other of 

 a small species not determined — but without obtaining any results. 

 The flounder died from lack of pure water due to my inability to 

 provide for him an aquarium of sufficient capacity. The other fish 

 was kept alive for a week or more and lirought back to Cambridge 

 in good condition, but finally escaped over the side of the dish in 

 which he was kept and when found was dried stitf and hard. The 

 single worm already mentioned, which was found in one of the lobsters 

 dissected in the laboratory, I fed to a large minnow (Fundulus) ^Yhich 

 was kept in a salt-water aquarium. On my return to Cambridge 

 after an absence of five days I found the minnow dead apparently 

 from failure of the aerating apparatus; no trace of the Stichocotyle 

 was found on dissection. Thus my experiment came to naught. 



When the young worms were set free from the cysts and placed 

 in sea-water they seemed very lively and for a long time kept up 

 the contractions and elongations of their bodies in a very animated 

 way. Their capacity for extending and drawing together the body is 

 quite remarkable and surpasses that which I have seen in any other 

 Trematode. The extent of their motion is comparal)le to that seen 

 in the "neck" region of Distomum cygnoides; but in Stichocotyle tiie 

 same power appears to be uniformly present throughout the whole 

 length of the body. Stichocotyle seems in fact not at all inferior to 

 the leeches in this respect. Its progression is accomplished in a 

 manner similar t(» that of lYematodes in general, i. e. by fixing the 

 postérieur region of the body by means of one or more suckers while 

 the anterior part reaches forward and attaches itself by means of 

 one or more of the anterior suckers; this is followed by the loo.sening 

 of the posterior attachment and the drawing uj) of the hind end of 

 the body to the anterior point of attachment, The suckers may be 



