CONTEIBUTIONS TO AMEBICAN HELMINTHOLOGY. 67 



genital apparatus, and I propose for its reception tlie generic name 

 " Sphyranura," with the following characters : 



Body depressed, somewhat elongate, expanded posteriorly into a 

 caudal lamina, considei'ahly wider than the body, bearing two im- 

 mersed acetabula, two large hooks behind these, and sixteen small 

 hooks (seven along each side of the lamina, and one in the centre of 

 each acetabulum). Mouth ventral anterior, somewhat funnel-shaped, 

 intestine with two branches anastomosing posteriorly. Excretory 

 pore between the acetabula, two contractile bladders antei'iorly. 

 Oviparous. Parasitic on the gills and in the mouth of perenni- 

 branchiate Amphibia. 



The specific characters in the allied genera are derived chiefly from 

 the size, the caudal and genital armature, and the size and shape of 

 the eggs. I accordingly note the following as characteristic of this 

 species, which I proj)ose to associate with the name of Dr. Osier as 

 S. Osleri, n. sp. (Figs. 12, 13, 14.) 



Body 2.6 mm. in length by 0.7 mm. in breadth, narrowed at 

 each end, especially where it joins the caudal lamina, which measures 

 1 mm. across, and about 0.45 mm. in length. Large hooks 0.2 mm. 

 long. Oviduct occupjdng the interval between the intestinal coeca, 

 with numerous eggs ; uterus with single mature egg, oval, with 

 brownish-yellow shell, 0.364 mm. x 0.247 mm. 



I am not aware that any monogeneous Trematode, with the ex- 

 ception of Polystomum integerrimum, has been hitherto found in 

 any amphibian; and this seems to be restricted to the tailless forms. 

 A careful examination of the gills, mouth-cavity, and urinary bladder 

 of both perennibranchiate and caducibranchiate Urodela would pro- 

 bably yield interesting results with regax'd to this family of Trema- 

 todes. 



I regard the foi'm under consideration as of great interest in view 

 of the frequently asserted^® relationship between Dactylogyrus and 

 Gyrodactylus on the one hand, and Polystomum on the other, and I 

 propose to recur to this after detailing the facts which I have been 

 able to elucidate with the material afc my disposal. 



2« Von Siebold, Untersuchungen iiber Gyrodactylus. Van Beneden, Animal Parasites, Eng. 

 Ed., p. 261. WLUemoes-Suhm, Zeit. f. wiss. Zool. XXI. I have not seen this paper. The 

 following is from Hofmann und Schwalbe's Jahresberichte fur 1872, p. 274 : " Hat Zeller den 

 Lebenslauf der Thiers vorziiglich aufgeklart so gebiihrt Willemoes-Suhm die Prioritat der 

 Publicirung der Besehreibung der Larve, sowie die Andeutung, dass die Aehnlichkeit derselben 

 mit einem Gyrodactylus eine phylogenetische Entwickelung von Polystomum und GyrodactyVus 

 aus einer Stammform wahrscheinlich mache." 



