476 Dr. O'Bryen Bellingham on Irish Entozoa. 



bladder. The species of the genus Trichosoma are all exceedingly 

 small and resemble each other very closely (almost the only dif- 

 ference being a little greater or less length or thickness of the 

 body), and as male and female are not always found together, it 

 is very difficult to determine the species accurately ; in fact, of 

 the twenty-two species which Rudolphi has enumerated, sixteen 

 are doubtful ; and of thirteen species which I have met with nine 

 are doubtful. 



1. Trichosoma obtusum ? Caeca of horned owl (Otus vulgaris). 



n . jj * f Small intestine of missel thrush (Turdus 



2. innexum r . < . . v 



J viscivorus. 



o , . , M f Small intestine of domestic fowl ( Gallus 



S - lonpcollel { a omesticus) . 



. j. f Urinary bladder of dog (Canis fam iliaris). 



~~ ™ ' \ Urinary bladder of fox (Canis Vulpes). 



Species dubice. 



5. Trichosoma Urinary bladder of wild cat (Felis Catus). 



fi f Small intestines of weasel (Mustela vul- 



' \ garis). 



7. * Urinary bladder of rat 1 ,„, , x 



8. Small intestine of rat) <** *"«««»)• 



q f Stomach of hedge- hog (Erinaceus vul- 



' \ garis). 



* This species of Trichosoma I have very frequently found in the 

 urinary bladder of the common Norway rat ; in some cases only one 

 or two occurred, in others six, eight or upwards. Many were free 

 in the bladder ; others so firmly attached by their anterior extremity 

 to the mucous membrane, that they broke across when pulled ; and 

 some even remained adherent after having been placed in spirits of 

 wine. They are the largest species of Trichosoma which I have seen, 

 the posterior division of the body in some being so thick as in a cer- 

 tain degree to resemble this part in the Trichocephalus, from which, 

 however, they are readily distinguished, the increase in diameter 

 being gradual, and not sudden. They are about 8 lines in length, 

 the body white and cylindrical, the posterior extremity rounded ; in 

 the thicker part of the body the alimentary canal appears to be some- 

 what spiral, and is surrounded by the convoluted ovaries. All the 

 specimens which I have appear to be females. 



This species has not, I believe, hitherto been described, although 

 it is very common, and I have frequently met with it. It occurs in 

 the urinary bladder, both of the male and female rat, and is quite 

 distinct from the species which inhabits the small intestine of the 

 same animal. 



From the thickness of the posterior part of the body compared 

 with other species of Trichosoma, I would venture to suggest for this 

 species the name Trichosoma crassicauda. 



