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4. On Galactosomum cochleariforme Rudolphi. 
By H.S. Pratt, Haverford College, Haverford Pa. 
(With 5 figures.) 
| eingeg. 27. April 1911. 
In a collection of trematodes which obtained at Tortugas, Florida, 
last summer, while working in the Laboratory of the Carnegie Institution 
of Washington situated on that island, was one species which infests 
the intestine of the frigate bird (Fregata aquila). This worm, as was 
first pointed out to me by my friend Dr. Teodor Odhner of Upsala, is 
identical with a trematode first described by Rudolphi in 1819 and 
named by him Distoma cochleariforme, and which had been collected by 
Natterer in Brazil from the frigate and several similar birds. Rudol- 
phi’s two original specimens have since been studied by Braun! who has 
made the species the type of the new genus Microlistrum. These spe- 
cimens were not, however, in a sufficiently good condition of preservation 
to enable Braun to detect the fact that the worms are not distomids 
at all but monostomids of the genus Galactosomum Looss, and similar 
in general organization to G. lacteum Jägerskiöld?, and that what he 
took for the acetabulum is really a penis-like organ in the genital sinus. 
G. cochleariforme is an interesting worm on account of the peculiar 
structure of certain of the genital organs. These are, however, very in- 
sufficiently known at the present time, notwithstanding the fact that 
the worm was first described almost a hundred years ago, and a detailed 
description of them will be welcome. 
‘ The body of the worm is about 8 mm long and is made up of two 
portions, a broad, flat anterior portion about 2 mm long and 1,5 mm 
wide, and an elongate posterior portion about 1 mm wide. The forward 
portion is thin and lamellate and extremely muscular, while the hinder 
portion is much thicker, having a plain ventral and a high-arched dorsal 
surface. The entire body is covered with short spines. The oral sucker 
is rather small, and a short prepharynx, a large pharynx and a very 
short oesophagus are present. The two intestinal trunks pass at once 
to the right and left sides of the body and then to its extreme hinder 
end. Lying between the forward portion of the intestinal trunks and 
also alongside the pharynx and prepharynx are numerous large gland- 
cells, similar to those present in @. lactewm (fig. 1, 4). They are not, 
however, so numerous and do not occupy so large a space as in that 
1 M. Braun, Fascioliden der Vögel. Zool. Jahrb. Abt. f. Syst., usw. Bd. 16. 
S. 56. 1902. i 
2L. A. Jägerskiöld, Uber Monostomum lacteum n. sp. Festskrift for 
Lilljeborg. p. 165. 1896. 
