486 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [34] 



Larval state. — Great numbers of encysted Rhynchobothria were found, 

 mostly in capsules, between the mucous and submucous coats of the 

 stomach of the Squeteague {Gynoscion regale) and the Bluefish (Poma- 

 tomus saltatrix), which appear to be the young form of this species. 

 The proboscides and their hooks agree. The bothria and their lobes seem 

 to be identical. The sequence from these fishes to the Dusky Shark 

 is a natural one, and in the absence of any evidence to the contrary it 

 may be fairly assumed that they are the encysted larva3 of R. bisulcatum. 

 It is the purpose of the author to publish figures and a fuller descrip- 

 tion of these in a subsequent paper. 



Habitat. — Strobile: Dusky Shark (Carcharias obscurus); pylorus and 

 iutestiue; very abundant. 



Scolex encysted: Squeteague (Cynoscion regule), Bluefish (Pomatomus 

 saltatrix)', submucous coat of stomach and peritoneum; very abundant. 

 Wood's Holl, Mass., August. 



This worm resembles R. paleaceum Rudolphi and Van Beueden. 

 (Dies., Revis. d. Ceph. Ab. Par., p. 294.) 



Tetrarhynchus Ungualis Van Beneden (Les Vers Cestoides, p. 151, tab. 

 xvii, 4, G-9). It presents many differences from Van Beneden's figures 

 and descriptions, however, among which may be mentioned here, as of 

 most importance, the number and form of the hooks, the articulation of 

 the neck with the body, and the position of the male genital openings. 

 Van Beueden represents the latter in R. paleaceum as always opening 

 at the posterior third of the segments. In all of the different forms of R- 

 bisulcatum they open uniformly near or in front of the anterior third. 



Rhynchobothrium tenuicolle Budolphi. 

 [Plate V, Figs. 17,18.] 



Tetrarhynchus tcnuicoUi* Rud., Synops., 130 and 451. Creplin, Erscb. and 

 Grub. Encycl., xsxli, 295, note 34, and Ericbson's Arcb., 1846, 149. Du- 

 jardiu, Hist. Nat. des Helmintb., 551. 



rihyHchobothrium tenuicolleDiesmgi Sitzungsb., xiii, 1854,595; aud Revis. der 

 Cepb. Ab. Par., 299. 



Tetrarhynchus coroUatua Siebold, Zeitscb. fiir Wissenscb. Zool., ii, 241 (in part). 



The characters given for this species by Diesing are the following: 

 Dead with suborbiculate lateral bothria, converging at the apex aud 

 with an. elevated border; neck very long, subcylindrical, slender, rounded 

 at the base ; segments of the body bacilliform, ultimate ones contracted, 

 easily falling off. Length of head and neck, 5.3 mm to G.5 mi " ; length of 

 body, 15 mm to 17 min ; breadth, 0.56 mm . 



The proboscides for the larval condition are described as filiform, very 

 slender, and armed with a long series of ternately verticillate and re- 

 curved hooks. 



The published descriptions of this species are meager and unaccom- 

 panied with figures. It is with some hesitation, therefore, that I refer 

 a few Rhynchobothria from the spiral valve of the Smooth Dogfish (Mus- 

 telus canis) to this species* 



