Scolex polymorphus. 



164 Dr. O^Bryen Bellingliam on Irish Entozoa. 



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

 confined almost exclusively to fish, never oeciuTing 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- 

 thocephalus, 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 

 (fom- of which were doubtfrd) ; 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- 



manda). 

 Pyloric appendages of ling (Lota Molva). 

 Intestines of conger-eel (Anguilla Conger). 

 Intestines of lump-sucker (Cyclopterus Lum- 

 pus). 



Genus 15. Tetrabhynchus. 



(Derived from rcTpas, quatuor, and pvy^^os, proboscis.) 



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

 posterioriy 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 Tetrarhxjnchus. It 

 is not niunerous in species, twelv^e only being enumerated by 

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

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

 or birds. They seldom inhabit the ahmentary canal. 



, ™ _, 7 7 * r Abdominal cavitv of salmon (Salmo Sa- 



1. Tetrarhynchns grossus * . < , ^ • ^ 



o Tj J, /T-> j\ f Abdominal cavity of sal- 



2. 50/mM5 T (Drummond). < ^c- ? o / \ 



^ ''I 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 so/ic?M5 was discovered and named by my friend 



