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 reqviested 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 a-gth 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^otli 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 joints had become detached from the Strol)ila, and had . 

 attained their sexual maturity independently ; a view, which, if confirmed by subsequent 

 observation, will render the individuality of each proglottis remarkably significant. 



A2:>pe7idix. — 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. Erom the 

 Perch I have obtained two forms of Echinorhynchus, accompanied by a solitary example 

 of the well-known viviparous Nematode, Cucullmms elegans. Being an adult female, it 

 contained germs, eggs, and young in every possible stage of development. From a 

 Pike I procured three very juvenile examples of THcuspidaria nodulosa. In this para- 

 site, and in immediate connexion with the sub-epidermal calcareous corpuscles, I have 

 discovered peculiar vessels with flask-shaped ends, the latter surrounding the corpuscles. 

 I have akeady 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. 



Erom the intestines of a large snapping Turtle {Chehjdra serpentina) I have procured 



* Vol. vii. in Memoranda, p. 115 and p. 202. 



