382 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



well to the left, opposite the edge of the left cecum, it is apparently me- 

 dian in some specimens, otherwise in perfect agreement with H. mutabile. 

 Both of these variations are unusual within a species of trematode. In 

 fact, one of the 3 specimens in the present lot shows a genital pore almost 

 median in position. The cirrus sac extends to the left but bends back me- 

 dianly near its tip. When the cirrus sac is straight, the genital pore is to 

 the left. 



These variations arouse some question as to the validity of H. epineph- 

 eli Yamaguti, 1934 and H. lethrini Yamaguti, 1934. Specimens of H. 

 epinepheli kindly sent to me by Yamaguti show the dorsal preacetabular 

 confluency of the vitellaria. But the genital pore is constantly median and 

 H. epinepheli may be a valid species. H. lethrini differs in the anterior ex- 

 tent of the vitellaria. 



The specimens from Mycteroperca xenarcha (?) (the identification 

 of the host is somewhat uncertain) all agreed in showing a short, narrow, 

 and pointed posterior region of the body; but, since other details agreed 

 with H. mutabile, the pointed posterior end is interpreted as an individual 

 variation. 



The genus Hamacreadium is so similar to Plagioporus (= Lebouria) 

 and to Podocotyle that its validity might be questioned. Yamaguti empha- 

 sizes the anterior extent of the excretory vesicle. The median genital pore, 

 although not constant in Hamacreadium, is usual, whereas it is never me- 

 dian in Plagioporus. The ovary is always lobed in Hamacreadium and 

 rarely so in Plagioporus. In Podocotyle the testes are tandem (possible 

 exception — P. atherinae Nicoll), the excretory bladder not anterior to 

 the acetabulum, the vitellaria not anterior to the acetabulum, the genital 

 pore to the left. 



Hamacreadium oscitans Linton, 1910 



Host: Anisotremus interruptus (Gill) 

 Location: Intestine 



Locality: Sulivan Bay, James Island, Galapagos 

 Frequency : One specimen collected 



Hamacreadium oscitans was described by Linton (1910) from Tor- 

 tugas, Florida, from the following hosts: Haemulon plumieri, H. sciurus, 

 and Anisotremus virginicus. The writer has collected it at Tortugas from 

 Anisotremus virginicus and A. carbonarium (the latter a new host 

 record). 



