478 Dr. O'Bryen Bellingham on Irish Entozoa. 



2. Trichocephalus crenatus * . . Caecum of pig (Sus Scrofa). 



3. nodosus .... Csecum of mouse (Mus Mus cuius). 



Genus 4. Oxyurus. 

 (Derived from 6£vs, acutus, and ovpa, cauda.) 



Body cylindrical and elastic, the posterior extremity subulate in the 

 female ; mouth orbicular and terminal ; male organ contained in a 

 sheath. 



The genus Oxyurus was established by Rudolphi ; it contains 

 a very small number of species, only three being enumerated by 

 Rudolphi in his ( Synopsis/ The species inhabit the large in- 

 testines of the mammalia, and have not been found in either 

 birds, reptiles or fish. 



1. Ovyums curvula t { **%&**" ° f h ° rSe ( *" ^ 



2. ambigua \ Csecum of rabbit (Lepus Cuniculus). 



Genus 5. Cucullanus. 



(Derived from cucullus, a hood.) 



Body cylindrical and elastic, obtuse anteriorly, more attenuated pos- 

 teriorly ; mouth orbicular ; head provided with a striated cucullus 

 (from which circumstance the genus has been named) ; anus ter- 

 minal ; orifice of female organs a little behind the centre of the 

 body ; male organ a double spiculum ; all the species viviparous. 



The name Cucullus was given to this genus by Miiller ; the 

 species inhabit the alimentary canal of fish, and do not occur in 

 either mammalia or birds. 



f Stomach, intestines and pyloric appen- 

 1. Cucullanus elegans§ . . < dages of perch (Percafluviatilis). 



l_ Intestines of eel (Anguilla acutirostris). 



* This species resembles pretty closely the Trichocephalus dispar ; 

 the capillary portion of the animal is, however, a little longer, and 

 the sheath of the penis has a somewhat different shape from what it 

 has in that species. 



f The Oxyurus curvula is noticed in Pennant's ' British Zoology ' 

 under the name of Trichocephalus Equi ; it is the largest species of the 

 genus, inhabiting the great intestine of the horse, and is not at all 

 uncommon. 



X I have found the Oxyurus ambigua in great numbers in the 

 csecum of the common wild rabbit ; the females are double the length 

 of the males, and much more numerous. The mouth is orbicular and 

 very small ; on each side of the head is a transparent membrane, 

 somewhat resembling that of the Ascaris vermicularis. 



§ The Cucullanus elegans is very common in the perch, occurring 



