Dr. O'Bryen Bellingham on Irish Entozoa. 165 



Genus 16. Ligula. 

 (Derived from ligula, a strap.) 

 Gen. Char. — In the first degree of its development. Body very long, 

 flat, continuous, without articulations, having a central longitu- 

 dinal depression ; without any appearance of head or of organs of 

 generation. 



In the perfect state. Body very long, flat, continuous, with- 

 out articulations. Head provided with a simple depression upon 

 each side ; ovaries in a single or double series, with the lemnisci 

 in the median line. 



The genus Ligula was established by Bloch and Goetze, and 

 has been adopted by zoologists since. The species are not nu- 

 merous, seven only being enumerated by Rudolphi. They occur 

 in birds and fish (principally the fresh-water species) ; one spe- 

 cies has been found in the seal (Phoca vitulina). They inhabit 

 the abdominal cavity of fish, and the alimentary canal of birds. 



The opinion put forward by Rudolphi of the mode of develop- 

 ment of the Ligula is curious, viz. that it begins life in fish, and 

 arrives at its perfect state of development in birds which feed 

 upon these fish. He founds his conclusion upon the fact, that 

 the Ligula occurs only in the peritonseal cavity of fish and in the 

 intestinal canal of birds ; in addition, he has never, in the Ligula 

 of fish, found the ovaries developed as they are in birds ; and in 

 Austria, where the fish which commonly contain Ligula do not 

 occur, he never could discover the Ligula in the aquatic birds. 

 However, Bremser does not coincide with Rudolphi upon this 

 point ; and De Blainville asks very naturally, what is the use of 

 the ova being developed in the ovaries of the Ligula of birds ? 

 and how do these find their way into the abdominal cavity of fish ? 

 The Ligula appears to be the only species of Entozoon ever 

 used as food by man. I have learned from my friend Dr. Scouler, 

 that in some parts of Italy where the Ligula is particularly abun- 

 dant in the fish, this species affords a favourite food to the people. 



T . 7 f Small intestines of crested grebe (Podiceps crista- 



Liigula sparsa. < x ° v r 



Dr. Drummond of Belfast, who was kind enough to communicate 

 specimens to me ; recently I found a single specimen of this species 

 in the abdominal cavity of the salmon (Salmo Salar) ; it lay loosely 

 attached to the peritonseal coat of the intestines by the proboscides 

 of the head. I can bear testimony to the accuracy of the description 

 given of it by Dr. Drummond, which is contained in the same vol. of 

 the ' Mag. of Nat. Hist/ as that last noticed, and is illustrated by 

 several figures. I shall only add, that in the recent animal a num- 

 ber of bodies like ova were seen, with the assistance of a lens, upon 

 each side of the depressions on the head, lying apparently under the 

 integuments. 



