114 NEW GYRODACTYLOID TREMATODES PROM AUSTRALIAN FISHES, 



of the intestine, but undergoes a gTeat development in the mid-region of the 

 body, there occupying a considerable area immediately anterior and posterior 

 to the testis, when it stretches right across the body so as to encircle the male 

 gland. The yolk is transferred to the female tubes by a pair of transverse 

 yolk-ducts, situated considerably anterior to this region. No eggs were present 

 in the specimens examined. 



From the gills of the common marine bream (silver bream), Sparus aus- 

 tralis Guntlier, from Moreton Bay. 



Subfamily IV. MERIZOCOTYLINAE, n. subfam. 



Syn. AnisocotyUnae MonticeUi, 1903 (in part). 



Gyrodactylidae in which the disc is provided with suckers as well as major 

 hooks. Cephalic glands open by distinct head-organs. Testis single or double. 

 Gvary unbranched. Vagina present. 



From the gills and nasal glands of marine fishes. 



This subfamily includes the following genera: — Merizocotyle Cerfontaine and 

 Empruthotrema J. and T. 



21. Merizocotyle Cerfontaine, 1894. 



Medium-sized worms, in which the disc is provided with a small number 

 (five to seven) of central suckers and a ring of from twelve to eighteen mar- 

 ginal suckers, the latter provided each with a minor hook. Two major hooks 

 present. Four eyes. Cirrus simple. Testis and ovary single and compact. Two 

 vaginae present (according to MacCallum). Vitellaria well developed. 



From nasal gland and gills of stingrays in America and Europe. 



Type s p e c i e s, 3f . d/iapliana Cerf . 



This genus has been placed by various authors in the Monocotylidae, Ani- 

 socotylinae and Tristomdae. The presence of distinctly glandular head-organs 

 undoubtedly shows its relationship with the Gyrodactylidae. At the same time 

 the double vagina and the remarkable "sucker-disc" are characters which dis- 

 tinctly separate the genus from members of any other subfamily belonging to that 

 family. (See also under genus Loplweutyle) . 



Ivnown species: — M. diaphana Cerf., 1894; M. minor Cerf., 1898; M. dasy- 

 batis MacCallum, 1916. 



22. Empruthotrema, n.gen. 



Medium-sized robust Merizocotylinae, about 1.6 mm. in length, in which the 

 disc is nearly as wide as the body, and is provided with fourteen marginal and 

 five central suckers. Major hooks are absent, but minor hooks are found mar- 

 ginally, one between each pair of suckers. Anterior end broad and provided 

 with three head-organs, doubtless glandular. Small pharynx; short oesophagus. 

 Intestinal limbs end blindly. Testis double and very large; penis fairly simple. 

 Ovary compact; shell-glands strongly developed. Vagina paired. 



Fi'om the gills of Eaja erinacea — Massachusetts. 



Type s p e e i e s, £. raiae (Ma.cCallum, 1916) . 



This species has been described and flgui-ed by MacCallum as a species of 

 Acanthoeotyle, a decision which is obviously incorrect. The author does not 

 mention the presence of cephalic glands, but his figure suggests that they do 

 occur; in almost every other respect the worm is closely allied to Merizocotyle. 



