History of the Nematode Worms. 547 
markable difference consisted in the posterior pharyngeal dila- 
tation (which was previously cordate) having increased consider- 
ably in length, and acquired seemingly a granular appearance 
in its interior. The chitinous coat of the buccal cavity was some- 
what tougher, and the commencement of the genital organ was 
enlarged. In front of this two clear vesicles of considerable size 
were to be seen—undoubtedly the nuclei of the two colossal 
glandular cells situated here in nearly all Strongylide, which 
open outwards through the porus excretorius. The worms were 
but little increased in size. 
A few days later (ten days after transfer) I found a further 
stage of development in a dog: this was characterized by a 
stouter form and the possession of a chitinous buccal funnel, 
and had been produced, like the above-described second develop- 
mental form of Cucullanus, from the earlier larval form by a 
change of skin. As in Cucullanus, moreover, the structure of 
the buccal cup was not the final one. It was scarcely more than 
a simple clothing of the funnel-shaped buccal cavity ; whilst the 
buccal armature of the mature Dochmius has a rather compli- 
cated structure, and is composed of a number of separate skeletal 
pieces. Posteriorly, however, the buccal armature was already 
continuous with the horny linng of the pharynx. The 
sexual] distinctions could not yet be made out, the sexual organs, 
notwithstanding their increased size, still retaining their primi- 
tive organization. 
The intermediate stage here described, however, is of but 
short duration, and passes without interruption into the mature 
stage (in this respect differmg from Cucullanus, in which it is 
attained within the intermediate host). Twelve days after the 
transfer we see the young animals (now 2 millims. in length) 
acquire the definitive Dochmius-form by a change of skin. The 
buccal cavity is produced behind the provisional funnel, and is 
at first clothed only with a thin and colourless coat, which, 
however, soon shows that it 1s composed of separate pieces. 
In the course of two more days the young Dochmi measure 
3-5 millims. The genital organs are more or less increased, and 
in the males even fully developed, although still without mature 
seminal corpuscles. The female organs seem to require a longer 
time for their development. The ovaries especially, which im 
the smaller animals were seated upon the so-called uterus as 
short and thin, horn-like diverticula, had already, in the larger 
specimens, grown through a considerable portion of the body- 
cavity, and formed many loops, without, however, anywhere 
attaining their full length or enclosing mature ova. 
[To be continued. | 
