Miscellaneous. 163 



sacs, tore it out of the tentacle, and swallowed it. Several other 

 similar experiments gave the same result. The most interesting 

 was one in which, a mealworm having been placed side by side 

 with a iSuccinea, the author saw a blackcap seize first the Lenco- 

 chloridhc7n and afterwards the mealworm. In all these experiments 

 it was observable that the bird, after having seized the Leioco- 

 clihiidium and torn it out with a single strike of the bill, 

 swallowed it, sometimes immediately, sometimes only after striking 

 it several times against the floor of its cage or the perch, thus 

 behaving exactly as the insectivorous birds do with their ordinary 

 food. 



From the success of these first experiments Dr. Zeller had great 

 hopes of being able to confirm his hj^^othesis by the autopsy of the 

 birds. So his disappointment was great when he did not find a 

 single Distomum macvostomuni in three redbreasts and a blackcap 

 which he dissected some weeks after he had seen them swallow 

 the Leucochloridia. He then questioned whether the larvae of Dis- 

 tomum contained in the LeucoMoridia had been quite mature, or 

 whether, perhaps, the artificial nourishment of the birds might not 

 have exercised an injurious influence upon the parasites. In order 

 to avoid these causes of failure he made fresh experiments, employ- 

 ing this time some Succinece which had been kept for a long time 

 in captivity, and containing Distoynum-larysc, the development of 

 which could not but be sufficiently advanced ; and at the same time, 

 instead of cage-birds, he made use of young birds in a free state, 

 but still in the nest. These birds were shut up with their nests in 

 small cages, and left in a place where they could be fed by their 

 parents. 



Three series of experiments, made under these conditions, upon 

 whitethroats (Curruca gamda), blackcaps, and wagtails were 

 crowned with full success. The Distoma were fixed in the rectum 

 in great numbers and very lively ; their reproductive organs pre- 

 sented a state of development more or less advanced, according to 

 the length of time they had remained in the intestinal canal of their 

 host. In some of them the oviducts were to be seen filled with ova, 

 some of which even were already of an intense yellow colour. The 

 development of the larva of Distomum macrostomum into the adult 

 animal is very rajnd; and the production of the ova seems to com- 

 mence within six days after the migration. 



Dr. Zeller completes his memoir with some observations on the 

 species allied to D. macrostomum, and upon the hosts which furnish 

 nouiishment for these difi'erent species of Distomum. He con- 

 siders that Diesing was wrong in combining with D. macrostomum 

 the D. erraticum and D. rimjens of liudolphi. On the other hand, 

 he convinced himself that D, mesostomnvi, Rud., which occurs in the 

 song-thrush, the grosbeak, the bullfinch, and the greenfinch, is 

 quite distinct from D. macrostomum. But D. JioJosiomum, Hud., 

 from the water-rails and the common water-hen, which M. von 

 Siebold supposed to bo the adidt form of the larva of Leucochlori- 



