Dr. O'Bryen Bellingham on Irish Entozoa. 255 



and the term has been adopted by all zoologists since. The spe- 

 cies inhabit principally the alimentary canal ; they are most nu- 

 merous in birds and tish, less common in mammalia^ and still 

 more rare in reptiles. 



Two divisions have been made of the genus : in one the neck 

 and body are unarmed ; in the other this part is provided vai\\ 

 spines ; the species are further subdivided according to the shape 

 of the proboscis^ and to the absence or presence of a neck. 



Collo corporeque inermibus ; proboscide cylindrica vel lineari. 



'Stomach and intestine of perch 

 (Perca fluviatilis) . 



Intestine of eel (Anguilla acutiros- 

 tris) . 



Intestine of trout (Salmo Fario). 



Intestine of rudd {Cyprinus Ery- 

 throphthalmus). 



Intestine of gudgeon {Cyprinus Go- 

 bio). 



Intestine of three-spined stickleback 

 (Gasterosteus aculeatiis). 



Intestines of pike {Esox Lucius). 



1. Echinorhynchus angustatus* < 



* The Echinorhynchus anyustatus is common in the perch ; the co- 

 lour of this species is reddish yellow or white ; the longest specimen 

 I possess measures 4\ lines, including the proboscis ; the body is 

 nearly cylindrical, a little wider anteriorly however than posteriorly ; 

 the proboscis is cylindrical, about two-thirds of a line in length ; the 

 neck is short, seldom protruded fully, and nearly of the same dia- 

 meter as the proboscis ; the caudal pouch in the male is large : little 

 difference in size exists between the male and the female ; the male 

 however is much rarer than the female. 



This species may be preserved in fresh water for a sufficient length 

 of time to observe the manner in which the proboscis is protruded 

 and retracted ; as far as I have seen, the only mode in which this 

 organ is retracted is by inversion upon itself, that surface which had 

 been exterior when it was protruded becoming internal when it was 

 retracted ; the proboscis was always retracted slowly, and generally 

 protruded with great rapidity. 



The figure given by Miiller of this species in his ' Zoologia Danica ' 

 under the name Echinorhynchus Lucii, and that which Rudolphi has 

 given in his ' Entozoor. Hist. Nat.' under the name Echin. affinis, are 

 not good ; the proboscis is not at all so thick in proportion to the 

 body as they have represented it to be. 



The specimens of Echinorhynchus angustatus which I have found in 

 the eel and trout are perfectly white ; the longest measures nearly 

 six lines exclusive of the proboscis ; the body has a greater diameter 



