478 Dr. O'Bryen Bellingham on Irish Entozoa. 



2. Trichocephalus crenahis * .. Ciecum of p\g (Sus Scrof a). 



3. nodosus .... Caecum of mouse {Mus Musculus). 



Genus 4. Oxyurus. 



(Derived from olvs, acutus, and ovph, caucla.) 



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 establislied by Rudolplii ; it contains 

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

 E-udolphi in his ' Synopsis.^ The species inhabit the large in- 

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

 birds, reptiles or fish. 



„ , . f Largre intestine of horse (Equus Ca- 



1. Ojri/urus a,rvida\ | b^iHus). 



2. ambigiial Caecum of rabbit (Leptis Ciinicvlus). 



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 jMiiller ; the 

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

 either mammalia or birds. 



{Stomach, intestines and pyloric appen- 

 dages of perch {Percafluviatilis). 

 Intestines of eel {AnguUla acutirostris). 



* This species resembles pretty closely the Trichocephulus dispar ; 

 the capillar}'^ 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. 



t The Oxyurus curvula is noticed in Pennant's ' British Zoology ' 

 under the name of Trichocephulus Equi ; it is the Largest species of the 

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

 uncommon. 



% 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 ver}' common in the perch, occurring 



