PKOM A SAYORD-riSK. 203 



In 1802, Bosc described and figured a trematode under the 

 title of Fasciola fiisca. This he obtained from the intestines of a 

 Dorado. In form it differs considerably from any of the fore- 

 going species, with all of which, however, it is probably identical. 

 Bosc's description runs as follows : — " Brune, la partie posterieure 

 tres-renflee, presque ovale ; la partie anterieure mince, cylindrique, 

 inegale, avec deux petits tentacules en dessous. Le sugoir de 

 I'anus tres-grand " *. Bosc recognized the identity of his worm 

 with the Distoma Coryphencs of B-udolphi ; and systematists gene- 

 rally .have adopted his synonymy. In the British-Museum Cata- 

 logue the Fasciola fusca and F. ventricosa of Pallas are regarded 

 as one and the same species. If two small appendages did really 

 exist below the oral sucker, then Bosc's worm is certainly a dis- 

 tinct species. I have never seen anything resembling this amongst 

 the trematode parasites — though the exserted penis might very 

 well be mistaken for one such process. Helminthologists, gene- 

 rally, appear to have doubted the existence of such developments. 



In 1827, Nardo obtained two very large flukes from the stomach 

 of a fish captured in the Grulf of Venice during the month of Sep- 

 tember. He calls the fish Prostostegus prototypus, which appears 

 to be the same as the Luvarus imperialis of Eafinesque. One of 

 the parasites being no less than five inches in length and nearly 

 half an inch in breadth, he appropriately named the species 

 Distoma gigas, believing, naturally enough, that he had to, deal 

 with a new species. His description is as follows : — " Distoma 

 teres, rubrum, retractile ; poro ventrali minimo cujus apertura 

 magna, rotunda, ciliata ; poro antico terminali, parvo ; collo brevi, 

 retrorsum divergente, extensili, apice angusto, basi lato ; cauda 

 longa, postice incrassata et in apice obtuso osculo donata" f- 

 Here, again, a character is introduced the nature of which it is 

 extremely difficult to understand. I allude to the alleged ciliated 

 condition of the ventral sucker, an appearance perhaps due to a 

 wrinkled state of the lip. Apart from this I see no reason for 

 supposing this parasite to be distinct from the Distoma clavatum 

 procured by Mr. Guilding, or the Fasciola ventricosa described by 

 Pallas. The intestines of the fish in question harboured another 

 trematode parasite, to which Nardo applied the title D. Bayneri- 

 anum. This appears to be a distinct species ; but its size is not 

 stated. Unfortunately, Nardo gives no figure of his Distoma 

 gigas. It is by far the largest fiuke at present known. 



* Hist. Nat. des Vers, vol. i. (1802) p. 271. 



t Isis, for 1833, p. 523; from Heisinger's ' Zeitschrift,' 1827, p. 68. 



