CIIAP. V.] PARASITIC WORMS. 245 



which and the disc numerous large fleshy cirrhi of a 

 bright crimson colour project downwards, giving the 

 creature a remarkable aspect. No description of it, so 

 far as I am aware, has appeared in any systematic work 

 on zoology. 



Sea Slugs. There are a few species of Holothurice, of 

 which the trepang is the best known example. It is 

 largely collected in the Gulf of Manaar, and dried in the 

 sun to prepareTit for export to China. 1 A good descrip- 

 tion and figure of it are still desiderata. 



Parasitic Worms. Of these entozoa, the Filaria me- 

 dinensis, or guinea worm, which burrows in the cellular 

 tissue under the skin, is well known in the north of 

 the island, but rarely found in the damper districts 

 of the south and west. In Ceylon, as elsewhere, the 

 natives attribute its occurrence to drinking the waters 

 of particular wells ; but this belief is inconsistent with 

 the fact that its lodgment in the human body is almost 

 always effected just above the ankle. This shows that 

 the minute parasites are transferred to the skin of the 

 leg from the moist vegetation bordering the footpaths 

 leading to wells. At this period the creatures are 

 minute, and the process of insinuation is painless and 

 imperceptible. It is only when they attain to considerable 

 size, a foot or more in length, that the operation of ex- 

 tracting them is resorted to, when exercise may have 

 given rise to inconvenience and inflammation. 



Planaria. In the journal above alluded to, Dr. Ke- 

 laart has given descriptions of fifteen species of planaria, 

 and four of a new genus, instituted by him for the recep- 

 tion of those differing from the normal kinds by some 

 peculiarities which they exhibit in common. At Point 

 Pedro, Mr. Edgar Layard met with one on the bark of 

 trees, after heavy rain, which would appear to belong to 

 the subgenus geoplana. 2 



* See Vol. H. p. 556 ~ 



" A curious species, which is of 

 a light brown above, white under- 



neath j very broad and thin, and has 



R 3 



a peculiarly shaped tail, half-moon- 

 shaped, in fact, like a grocer's cheese 



knife, 



