356 DR. T. S. COBBOLD, FURTHER OBSERVATIONS ON ENTOZOA. 
The interest of this last-mentioned dissection did not altogether terminate here, as I 
was partly rewarded for my trouble by finding in the duodenum of the chicken a multi- 
tude of loose tape-worm joints, or proglottides in a somewhat unusual condition. There 
were also present a few imperfect Strobilas, whose joints had undergone no apparent 
alteration in form. Of course the loose joints had no genetic relation to the Entozoa 
which formed the subject of experiment ; but, viewed independently, they appeared of 
sufficient interest to demand separate investigation. Accordingly I requested Prof. Huxley 
to examine them, and he kindly assisted me in arriving at a true explanation of their 
character. These proglottides were more or less oval, rounded, compressed, semi-opake, 
whitish bodies ; to the naked eye discernible only by contrast with the coloured intestinal 
contents. They varied in size, the larger averaging -^-th of an inch in breadth ; these 
latter containing fully developed 6-hooked embryos. Each individual of the brood (fig. 16) 
was enclosed in an outer and inner envelope ; the middle pair of hooks, or boring appa- 
ratus, being simple and straight, and those of the lateral pairs lobed. The mature embryo 
measured 4-Juth of an inch in diameter over all. The point of interest in regard to these 
joints lies in the circumstance of their probable early separation from the head of the 
parent Strobila while living ; this being rendered likely from the fact that Prof. Huxley 
found among the proglottides a tape- worm head with only one joint attached. Although 
some days had elapsed since the chicken's death, the frozen condition of the bird had pre- 
vented any structural disintegration of the tissues of the worm-segments ; and I did not 
observe any free six-hooked embryos in the intestinal mucus. On the whole, therefore, it 
is fair to conclude that immature j oints had become detached from the Strobila, and had 
attained their sexual maturity independently ; a view, which, if confirmed by subsequent 
observation, will render the individuality of each proglottis remarkably significant. 
Appendix. — In this place, as on a former occasion, I have thought it useful to note 
down, more or less briefly, such other interesting forms of Entozoa as have incidentally 
come under my observation ; at least, I have here particularized a selection of them. 
Some of these parasites will elsewhere demand a more extended notice. Prom the 
Perch I have obtained two forms of Echmorhy nchus , accompanied by a solitary example 
of the well-known viviparous Nematode, Cucullanus elegans. Being an adult female, it 
contained germs, eggs, and young in every possible stage of development. Prom a 
Pike I procured three very juvenile examples of Tricnspidaria nodulosa. In this para- 
site, and in immediate 
I 
connexion with the sub-epidermal calcareous corpuscles, 
discovered peculiar vessels with flask- shaped ends, the latter surrounding the corpuscles. 
I have already described these structures in the ' Quart. Journ. Micr. Sc. * ' ; but I may 
here be permitted to add that, as they appear to be quite independent of the ordinary 
excretory system of vessels, I have since, on further consideration, arrived at the conclu- 
sion that they are rather to be regarded as special organs for the secretion and formation 
of the corpuscles than as a vicarious development of the excretory vascular system. 
Prom the intestines of a large snapping Turtle {Chelydra serpentina) I have procured 
* Vol. vii. in Memoranda, p. 115 and p. 202 
