82 Records of the Indian Museum. [Vol. IX 



The following list given by Linton will illustrate this fact : — 



Cestode. 



Usual or only known 

 final host. 



Tetrarhynchus hisulcatiis 



Rhynchobothriiim hulbifer 

 Rhynchobothrium speciosum 



Intermediate 

 hosts. 



Rhynchobothrium imparispine 

 Otobothrium crenacolle 



Carcharhinus obs citrus i8 species of Woods Hole 

 fishes. 

 ■ I 22 species of Beaufort 

 fishes. 



2 species of Bermuda 



fishes. 

 Mustehis cams . . 22 species of Woods Hole 



fishes. 

 Carcharhinus obscurus 12 species of Woods Hole 



fishes. 



3 species of Beaufort 



fishes. 

 5 species of Bermuda 

 fishes. 



4 species of Tortugas 



fishes. 

 Raia ocellata . . 28 species of Woods Hole 



fishes. 

 Sphyrna zygoena . . In a large number of 

 Woods Hole and Beau- 

 fort fishes, and in 3 Ber- 

 muda fishes; especially 

 abundant in flesh of 

 butterfish. 



In fresh water, similarly suitable conditions for the parasite 

 are found in Teleosts, as the larger forms of this group like Labeo 

 fohita, and the voracious Ophiocephalus striatus (which occasionally 

 attains a length of 3 feet or more), are seldom, if ever, prej^ed 

 upon. There are only two species of freshwater rays known in 

 India, viz. Hypolophus sephen (Mull, and Hen.) and Trygon fiuviatilis 

 (H.B.), measuring 5^ X 3I and 4^ X 2^ feet respectively. These are 

 not voracious, and it is improbable that either of them devoiir 

 large Teleosts. 



In the sea, Teleosts are frequently eaten by sharks and rays, 

 and hence we find that Teleosts under these conditions harbour 

 cystic forms only, and that these are capable of maturing and be- 

 coming adult in the intestines of their larger and more powerful 

 enemies. In this connection it has already been pointed out 

 (Southwell, 17) that marine Teleosts are not usually intermediate, 

 but collateral hosts to the parasite, and this statement receives 

 strong support from the conditions found to exist in freshwater 

 Teleosts. The larval forms of the parasites to be described have 

 not up to the present been found. It seems probable that they 

 will eventuall}^ be discovered encysted either in certain Copepoda 

 on which, Laheo rohita feeds, or on the mesenteries of smaller fish 

 such as are devoured by Ophiocephalus striatus. 



The following list comprises, as far as I have been able to 

 ascertain, all species of Cestodes which have been recorded from 

 Teleosts. It is compiled from the works of Rudolphi ( 16) , Lonnberg 



