42 SUMMARY OF CURRENT RESEARCHES RELATING TO 



D. micropharyngeum Lube, D. somaterise Lev., and two new species, 

 Gymnoplicdlus choledochus and O. bursicola,- — all from swimming birds 

 such as gulls. The name refers to the absence of a cirrus-pouch, but 

 the distinctive features are numerous. The nearest allies seem to be 

 among the Ccenogoniininse. 



Distomum arcanum.* — Prof. W. S. Nickerson describes this new 

 species, which lies hidden in cysts forming considerable swellings just 

 at the pylorus of American fro^s. It is closely related to several species 

 (D. medians, D. clavigerum, D. confusum), which it resembles in its 

 small size, compact form, spiny covering, rudimentary intestine, and 

 laterally placed sexual aperture, as well as in being parasitic in the 

 intestine of the frog. 



Genus Podocotyle (Duj.) Stoss.f — M. Liihe discusses the value of 

 this generic name, which was used by Dujardin as the name of a sub- 

 genus of Distomum, including those species with a stalked ventral 

 sucker, and was erected into a separate genus by Stossich. Liihe has 

 had an opportunity of examining Podocotyle furcata ( = Distomum fur- 

 ■catum Brems.), and has made out various points which should aid in 

 drawing up a generic definition. Thus he finds that, in addition to the 

 stalked ventral sucker, there is a smaller sessile sucker which lies be- 

 side the genital atrium, but does not envelope it. It is probable that 

 the stalked sucker is the homologue of the ordinary ventral sucker of 

 other flukes, and that the sessile sucker is an accessory structure. The 

 topography of the genital organs is also described, but the author notes 

 that, as Stiles and Hassall have taken D. angulatum Duj. as the type 

 of the genus Podocotyle, he cannot draw up a generic definition on the 

 basis of his own observations on D. furcatum, for it is quite uncertain 

 how far this species resembles D. angidatum. As Dujardin's description 

 of his own species is brief and unsatisfactory, the deadlock must con- 

 tinue till the species be re-found and re-described, and forms an object- 

 lesson illustrating the necessity for supreme care in the choice of type- 

 species. 



Genus Clinostomum (LeidyXJ — Prof. M. Braun sums up his various 

 brief notices on this subject in a general account of the history, general 

 characters, and species of the genus, with references and synonymy. 

 The genus is defined by the form of the body, which shows a division 

 into two regions, by the obliquely truncated anterior end of the body, 

 by the absence of a true pharynx and the shape of the alimentary canal, 

 and by the characters of the excretory and especially of the genital 

 system, in which the presence of a large uterine diverticulum (the 

 uterus-sac) is specially noteworthy. In the genus so defined the author 

 includes nine species, which are all fully described. He also notes a 

 number of young forms described by various authors, some of which can 

 be referred to existing species, while the position of others remains 

 uncertain. 



Hydatid Fluids. § — E. Couvreur analysed the fluid of a huge cyst 

 (Coenurus serialis) in a rabbit. There was no albumin, globulin, or 



* Amer. Nat., xxxiv. (1900) pp. 811-5 (1 fig.). 



t Zool. Anzeig., xxiii. (1900) pp. 487-92. 



I Zool. Jahrb. (Abt. Syst.), xiv. (1900) pp. 1-48 (2 pis.). 



§ Ann. Soc. Linn. Lyon, xlvi. (1900) pp. 73-4. 



