74 Transactions of the [Toui^a'i.'plTri^r^ 



this species is also jfigured under the same name by Bremser,* with 

 four fine Hnes running down from the anterior extremity; the 

 specimen of Eudolphi was taken from Baya Batis, that of Bremser 

 from the intestines of Squalus Gallseus. F. S. Leuckartf figured 

 the same animal and called it B. Planiceps ; the tentacles are re- 

 presented protruding, and he mentions four fine hnes or tubes, 

 continuations of the tentacles, each ending in a httle knob. 

 J. Miiller,t in speaking of these knobs and hnes in another species, 

 T. AUennatus fi'om the Sword Fish, suggested that they might 

 be the digestive organs. Von Siebold § named this species T. Co- 

 roUafus, and Blauchard|| called it PJujiichobothrius CoroUatus. 

 LeblondlF had before thought that he had found a Tetrarhynchus 

 parasitic in a trematode worm, and Professor Miescher** considered 

 that it was derived from a Filaria, which developed itself into a 

 Trematode and then into a Tetrarhynchus; but Von Siebold ft 

 clearly showed that both the supposed Filaria and the Trematode 

 were stages in the development of one and the same animal, viz. 

 T. CoroUatus. Van Beneden XI also described this stage, which he 

 called scolex in much the same manner as Von Siebold. Desir§§ 

 also gave a description of a very similar animal, which he called 

 Anthocephalus Scombri; the figures shghtly differ from those of 

 the others, but his description evidently applies to the same, species. 

 None of these authors mention any animal exactly like my speci- 

 men ; and although Van Beneden and Von Siebold, in speaking of a 

 T. Longicollis horn, intestines of Nurstelus Vulgaris, describe very 

 evident muscular fibres which cross each other diagonally, they say 

 nothing of striated fibres, neither do their figures show any. On 

 this point Kud Leuckart |1 11 remarks that " the muscular system 

 of cestodes consists of smooth fibres grouped together in bundles 

 more or less thick," In conclusion, I would remark that I consider 

 my specimen to be an undescribed larva of Tetrarhynchus Corol- 

 Jatus, the head closely resembhng in shape the head of that species 

 when matm-e, as figured by Eudolphi, the fine lines and little knobs 

 being the above-described proboscides atrophied fi-om being no 

 longer required for use when the animal had reached its ultimate 

 habitat in the intestines of the Eays or Sharks ; the scolex of Von 

 Siebold and Van Beneden, being much smaUer than mine, had not 

 advanced so far in development. 



* ' Icones Entozoorum,' Table x., Fig. 13. 



t 'Bruchstiicke Zoologisclies,' Part I., s. 21. 



X ' Miiller's Archiv.,' p. cvi. 



§ ' Z. W. Z.,' 1850, Bd. 2, p. 246 ; and ' A. S. N.,' 51. 



II 'A. S. N.,' 49, torn, x., 3rd Series. 



4 'A. S. N , 36, torn. vi. 



** ' Bericht iiber verhandlungen der nat. forsch. Gesellsehiift in Basel,' torn, iv., 40. 

 ft Loc. cit. 



%X ' Nouv. IMe'm. Aead. Roy. Belg.,' torn, xxiv., 50, p. 78. 

 §§ ' Archives do IMedecine Comparee," torn. i. 

 nil 'Die Mcnschlichcn Parasiten,' p. 168. 



