812 / - ' /^ rj r. CES TODK PA HA SITES F FTSHES— LINTON. 



circumference of the proboscis. Tlie remainder of the surface is cov- 

 ered witli niiiinte hooks ]>laced (slose together. Tliese minute hooks 

 also extend for a short distance between tlie spirals of larger hooks, 

 where they are a littk^ larger than they are on the outer surface of the 

 })roboscis. The larger spirals are about 0,09 mm. apart. 



No. 2 (fig. 0), sketch of alcoholic si)ecimen, embryo detached from 

 blastocyst to which it was firmly adherent: from Pomatomus saltafrix. 

 The bothria are doubtless distorted. The sketch was made with the 

 aid of a camera lucida, and represents exactly the appearance of the 

 embryo. It is quite difterent from other embryos, having the charac- 

 teristic hooks of R. erhiacens. Figure 7 is a sketch of a jwrtion of a 

 proboscis of this specimen. It will be seen that it agrees with the 

 si)ecimen from C. rctialc in every essential i)articular. Dimensions of 

 this interesting alcoholic specimen are as follows: Length, 2 mm.; 

 breadth of head, 1.08; diameter of neck, 0.34; length of contractile 

 bulb, 1 ; diameter of proboscis, excluding hooks, 0.00; length of stout 

 hooks, 0.00; breadth of same, middle of hook, 0.038: length of long, 

 slender hooks, 0.10(5; length of shortest hooks, 0.005. 



16. TETRARHYNCHUS ELONGATUS, Wagener. 



(Plato VII, fijrs. 9-12.) 



Anthocephalnx elongatns, Wagener, Nov. Act. 1. c. 57 aufl 81, pi. xvii, fig. L'lT; 

 XVIII. fig. 218. — DiESiNG, Revis. <1. cepb. Ah. Par., p. 313. — Olsson (Tctra- 

 rJujnchiis, statu scolecis), Lund's Univ. Arsskrift, IV, p. 9, pi. Ill, fig. 63. — 

 Leidy, Proc. Acad. Nat. Sci. Phil., 1890, p. 282. 



Under this title, I notice some larva^ of tetrarhynchus from the liver 

 of the sunflsh {Mota rotunda). 



The specimens (No. 5184, U.S.N.M.) were obtained from the United 

 States Fish Commission, having been collected oft" Marthas Vineyard, 

 Massachusetts, September 10, 1880, and sent to me for identification. I 

 therefore have seen them only in the condition of alcoholic specimens. 

 The specimens were still in the liver, which was, in places, tunneled out 

 by the parasites, and the latter were much broken, so that iu>ne of them 

 could be taken out entire. 



The blastocysts are subspherical at the anterior end, which contains 



the head and neck of the embryo. The i)Osterior end is elongated into 



a slender cylindrical body. When the head and neck portion is 



'liberated from the anterior end ot the blastocyst, it still remains 



in connection Avith the posterior slender part of the blastocjst. 



The diameter of the rounded anterioi- portion of one blastocyst was 

 5 mm. The posterior slender i)ortion, so much of it as was extracted 

 from the liver of the host, measured G5 mm. in length and 1.5 in diameter. 



One of the globular enlarged portions of a blastocyst was placed in 

 glycerine and left until thoroughly softened, then opened carefully, 

 and the embryo uncoiled. It was found to be continuous with the 



