810 



LARVAL CESTODE PARASITES OF FISHES— LINTON. 



14. TETRARHYNCHUS BISULCATUM, Linton. 

 (Plate VI, fig.s. 11-15.) 



lihymhobothriuin bisuhutiim, LiNTOx, U. S. Fish ("om. Kept., 1886, pp. 479-486, pi. 

 IV, tigs. 9-23; T. S. Fi.sh Com. Kept., 1887, pp. 8.-)7-861. pi. xiv, tigs, 10-12. aud 

 pi. XV, fig. 1. 



I have found a larval TctrHrhynclitiH, which 1 refer to this species, ou 

 a nuuiber of occasions and in a variety of hosts. 



Titrurhynchtia hisiilcatiim, rollerted at M'ooda Iloll, Mdnsachusetts. 



There were many finds from squeteague not included in the above 

 list. The favorite lodgment of this parasite is between the submucous 

 and mucous layers of the stomach. I have found it very abundant in 

 the squeteague at Woods Iloll, Massachusetts, and have seldom exam- 

 ined one of these fish without finding numerous examples of encysted 

 tetrarhjMichs in the stomach walls. 



The specimens from the squeteague appear to be typical scoleces of 

 T. hlsulvatnm. An alcoholic specimen yielded the following measure- 

 ments: Length of scolex, 1;G mm.; diameter of head, 0.04; length of 

 contractile bulbs, 0.42; diameter of proboscis, including hooks, 0.053; 

 length of longest hooks, 0.023. 



The cysts are small, oval; the blastocyst is also oval and is filled with 

 semifluid parenchyma with retractile granules. The embryo lies at one 

 end with the head pointing outward. It consists of the bothri;) and 

 short conical neck, the latter fitting over a very short terminal part 

 like a collar. 



A specimen from the flounder agrees, in general appearance and in 

 character of hooks, with type (alcoholic specimen): Diameter of pro- 

 boscis, including hooks, 0.0G2 mm.; length of hooks, 0.019. 



The specimen from the rudder-fish has a tumid neck, making it short 

 fusiform instead of conical, the usual sliape. 



The specimen from the scup agreed in general appearance. The pro- 

 boscides were retracted, only a few basal hooks showing. These were 

 small, 0.015 mm. in length. 



