Nos. IAND2.] COTYLASPIS IXSIGXIS. 3 



Plafyaspis, which latter however is probably identical with Coty- 

 laspis. Another genus, Aspidocotyle, is also known very inade- 

 quately. 



Material for the study of Cofylaspis can be had in abundance 

 at Chautauqua, but unfortunately it has only been possible for me 

 to be there during parts of July and August, so that I have not 

 had access to the material during the remainder of the year. The 

 flukes, as well as the hosts, bear transportation well, so that I 

 have been able to use them for histological purposes at other 

 times, but I have reason to suppose that the disturbance of their 

 natural environment reacts unfavorably on the reproductive or- 

 gans, and at any rate on the development, and that material should 

 be studied i)i situ for the embryology. 



The small size of the animal makes it available for study alive 

 under compression, and most of the parts have been examined in 

 this way. Compressed specimens have been killed and fixed, 

 preferably by means of saturated aqueous solution of corrosive, 

 then hardened in the same fluid and stained and mounted whole, 

 and preparations made in this way supplement the live animal. 

 The excretory system in its finer tubes can only be seen in the 

 living specimen. IMaterial was also hardened in various preser- 

 vatives for sectioning : Hermann's, Flemming's and Perenyi's 

 fluids .were used, also Mayer's picro-nitric, and saturated aqueous 

 corrosive sublimate solution. For general histological purposes 

 I found that the corrosive hardening was the best, followed by 

 iron-haematoxylin stain. I also tried using methylene blue intra 

 vitam. This demonstrated the muscular system beautifully but 

 has not as yet given me satisfaction with the nervous system. 



The .work on this article has been done in part in the laboratory 

 of the Chautauqua College of Liberal Arts, and in part in that of 

 Hamline University. I am especially obliged to Dr. \V. S. Nick- 

 erson for many valuable suggestions in connection with the best 

 technique for the study of trematodes, and for the use of his 

 manuscript of Cotylogastcr occidentalis. 



b. Distribution. 

 All my material was found in Lake Chautauqua, New York, a 

 glacial lake, twenty-five miles long and varying in width from one 



