178 ON PARASITES COLLECTED BY THE LATE CHARLES DARWITiT. 



Bistoma incerta. 

 X 35 diam. 



satisfied that the two forms are not identical (Trans. Linn. Soc. 

 vol. xxii. p. 364, pi. 63. figs. 6, 7). In like manner I have com- 

 pared it with Diesiug's Distoma clava (found by Natterer iu 

 Coluber flaviventris as well as in several allied 

 8. American snakes, including Cloelia faseiata, 

 in which latter host the worms were on one 

 occasion taken from the throat). Certainly, 

 Mr. Darwin's fluke corresponds with D. clava 

 more nearly than it does with D. Boscii, but 

 there are differences apart from the remarkable 

 disparity of size. In the new species the vitel- 

 laria are confined within the central part of the 

 body and the reproductive papilla occupies the 

 usual position, well above the acetabulum. 

 The eggs are very numerous, of a dark-brown 

 colour, having a long diameter of about x-,jVo"j 

 whereas the ova of -D. 5oscw measure fully y^" 

 from pole to pole. 



The remaining parasites are Ectozoa. 



5. Lernea bbanchialts. 



This species is marked : " Worm buried in the tail of a Gadus ; 

 T. del Fuego, Mar. 1833." Of the three specimens of female 

 epizoa, two were perfect. Excepting the length of the neck, 

 they differ in no essential from the ordinary species attached to 

 the gills of the Cod. In the example dissected, the neck was 

 imbedded beneath the skin to the extent of | of an inch, the so- 

 called head being branched in the usual manner. These epizoa 

 were included in the English collection of parasites at the Inter- 

 national Fisheries Exhibition, 1883. 



6. This refers to a solitary specimen marked : " Worm from 

 under branchial covering of fish ; T. del Euego, 1834." It is 

 evidently a leruean allied to the ordinaryi. hrancliialis, but dis- 

 plays a large number of loose filaments attached to and nearly 

 concealing the body. The head is wanting. Int. Eish. Exhib., 

 " List of Parasites," no. 23. 



7. Specimen marked : " Worm on scale of fish ; T. del Euego, 

 Jan. 1833." Eepeated examination of the scales and underlying 

 muscular fibres yielded no trace of any parasite. 



8. " Worm from branchige of iote or Gadus ; when caught 

 protruded a transparent case full of eggs ; T. del Euego, Jan. 

 1834." This lernean is also lost. 



