164 Dr. (VBryen Bellingham on Irish Entozoa. 



by all zoologists since. It contains but a single species, and is 

 confined almost exclusively to fish, never occurring in either 

 mammalia, birds or reptiles ; the alimentary canal is the usual 

 habitat, rarely the abdominal cavity. 



M. Leuchart looks upon the Scolex as the young of the An- 

 thocephaluSj but without reason. De Blainville, amongst other 

 characters, describes two red spots as seen at the posterior part 

 of the head of the animal ; I have only observed this in the Scolex 

 from the sole (Solea vulgaris) . Rudolphi in his first work, ' En- 

 tozoorum Historia Naturalis/ distinguished six species of Scolex 

 (four of which were doubtful) ; but in his last work, ' Synopsis 

 Entozoorum/ he admits but one species, the Scolex polymorphus. 



"Intestines of turbot (Pleuronectes maximus). 



Intestines and pyloric appendages of holibut 



(Hippoglossus vulgaris}. 



Intestines of sole (Solea vulgaris). 



• Stomach and intestines of dab (Platessa Li- 

 Scolex polymorphus. < 



Pyloric appendages of ling (Lota Molva). 

 Intestines of conger-eel (Anguilla Conger). 

 Intestines of lump-sucker (Cyclopterus Lum- 

 pus). 



Genus 15. Tetrarhynchus. 



(Derived from rerpas, quatuor, and pvyx<*s, proboscis.) 



Gen. Char. — Body flat, continuous, without articulations, terminating 



teriorly in a simple or forked extremity. Head provided 

 with two lateral bipartite depressions (appearing at times to con- 

 stitute four), and with four short retractile tentacula armed with 

 recurved hooks. 



This genus was established by Bosc under the name Hepa- 

 toxylon ; subsequently Rudolphi changed it to Tetrarhynchus. It 

 is not numerous in species, twelve only being enumerated by 

 Rudolphi. The species are almost confined to fish ; one occurred 

 in the turtle, but they have never been found in either mammalia 

 or birds. They seldom inhabit the alimentary canal. 



1. Tetrarhynchus grossus*. | Abdominal cavity of salmon (&/mo &- 



n tj j, /t\ j\ f Abdominal cavity of sal- 



2 - sobdus t ( Drammond )- { mon (Salmo Salar). 



* The Tetrarhynchus grossus I have inserted on Dr. Drummond's 

 authority, as I have not met with it. He has given a figure and de- 

 scription of this species in the second vol. of the new series of the 

 ■ Magazine of Nat. History/ p. 571. 



t The Tetrarhynchus solidus was discovered and named by my friend 



