Ou StlchocoJyle nepliropis CunniiiRliRni, a parasite of the American lobster. 455 



formed matter, which were caught while they were passing through 

 the previously formed cuticula to the exterior. Looss has ohserved 

 such a passage of formed material to take place in living Redia and 

 Cercaria and it is certaiidy not imi)rol)able that such i)articles would 

 be aflected by sUiius somewhat diti'erently from that material which 

 had already passed out, had come into contact with the surrounding 

 water and iiad therefore attained its ultimate condition. In certain 

 regions these globules are seen to be very numerous, while in others 

 adjacent to them they may be quite absent. No law governing their 

 distribution could be made out. 



Study of the peripheral parenchynia just beneath the muscu- 

 lature reveals in it also minute particles which agree in appear- 

 ance with the small spots seen in the cuticula. If these bodies 

 in the cuticula were degenerate nuclei, we might reasonably ex- 

 pect to discern differences in structure and staining qualities among 

 them. Those in ditîerent parts of the body should show transi- 

 tional stages leading from structures having sufficient resemblance 

 to nuclei to put their character beyond question , down through 

 various intermediate conditions to complete degeneration. But as 

 a matter of fact no such series can be made out and the only 

 difference between the structures is that of size. Moreover I have 

 in no case seen the larger globules in the younger posterior end of 

 the worm , but always in the anterior half of the body , where the 

 cuticula had attained the greatest thickness. 



This condition harmonizes with the theory that these spots are 

 due to globules of formed material passing out through the cuticula, 

 for the greater the thickness of the cuticula the greater the resistance 

 to the passage of such globules, and hence the greater the likelihood 

 of small globules flowing together to form larger ones. 



In the sections of one of my specimens killed in Merkel's fluid 

 and stained in Heidenhain's haematoxylin , the spots or vacuoles in 

 in the cuticula were especially numerous, and in many places there 

 were attached to the outer surface of the layer rounded globules 

 corresponding in form and size, as well as in staining quality, with 

 the globules still euclo.sed by the cuticula (PI. 30, Fig. 20). The 

 impression produced by the study of this specimen was, that the 

 slowly penetrating Merkei/s fluid had attected the outer portion of 

 the cuticula in such a way as to obstruct the passage of globules 

 outward before it had penetrated to the inner part of the layer: hence 

 the small globules united in the cuticula to form larger ones and 



