On Stichocotyle nephropis Cunuinghttui, a parasite of the American lobster. 449 



iiiiiuu uf the iutestiue aud the rectum. Though I examined the intestine 

 throughout its whole length in every infected lobster, in no case were 

 cysts found in any other part than that indicated. 



From these observations it would appear that this worm is much 

 less frequently present in Homarus than in Nephrops, for Cunningham 

 says in referring to the latter genus : "Usually out of a dozen opened 

 three or four are infected." According to my experience with Homarus^ 

 out of 100 lobsters opened only one is likely to be found infected. 

 It is to be said however that the lobsters used at the canning factory 

 were mostly of small size — between 9 and IO.'/l' inches in length — and 

 it is possible that in larger lobsters the proportion infected may be 

 somewhat greater. Among those which I opened were however a few 

 very large and evidently very old lobsters and in none of these was 

 any sign of infection observed. It is not improbable also that local 

 conditions may have an influence upon the number of individuals in- 

 fected. All of the lobsters received at North Haven were caught in 

 Penobscot Bay within a radius of perhaps 15 — 20 miles and it is 

 possible that lobsters from another locality might show eithei* a much 

 greater number of cases of infection or an entire freedom from the 

 parasite. 



Of the 100 or more uncooked lobsters dissected in the laboratory 

 (luring the past two years two have been found infected — one in 1893 

 by (30—70 worms and one in 1894 by a single one. These lobsters 

 were bought from dealers in Boston and the region in which they 

 were caught is not known. 



The greater part of the material which I collected was preserved 

 in eitlier a saturated solution of corrosive sublimate in Kleinenberg's 

 picro-sulphuric mixture + 5^/o acetic acid, or in Perenyi's fluid. 

 Either of these gives very satisfactory results, though the material 

 killed in the latter fluid has perhaps been of the most service 

 to nie. Neither of these reagents preserved the cilia which line the 

 excretcjry tubules in a satisfactory manner and the flame cells also 

 were not readily made out in the preserved worms. A number of 

 the worms were treated with the killing fluid while flattened under 

 the compressor; some of these, when stained faintly in Mayer's 

 HCl-cannine and mounted in balsam , allowed the excretory system 

 to be made out in a much more satisfactory manner than is possible 

 either in the living animal or from sections. For staining sections 

 either KnuLirn's or Boehmer's haematoxylin gave very good results, 

 especially if followed by eosin, though on some accounts the ammonia- 



