406 Zoological N. Y. Zoological Society. [I;20 



cound embedded in great numbers in the thyroid glands and 

 throughout the substance of the isthmus itself. 



When the muscular layers were carefully parted, the worm 

 was seen flattened in tangled layers. Some of these were seen 

 dangling from the surface in loops, the examinations being made 

 under water, as this was the simplest way to secure a view of 

 the parasites in situ. I have no doubt now that the loops are 

 broken off by the action of the gills and water and become en- 

 tangled in the meshes of the gills, doubtless for the purpose 

 of distribution in one way, since every fragment is loaded with 

 eggs. It is certain, however, that the local habitat of the worm 

 is in the cellular tissue under the skin and mucous membranes 

 of the branchial cavity and neighboring tissues of the throat, 

 including the space between the muscular fasciculi of the mus- 

 cular tissues of the isthmus. 



It may be said, that a great deal of time has been spent 

 with most careful and assiduous research in the endeavor to 

 find a whole worm. Out of the hundreds traced and teased out 

 only two whole worms have been secured and both of these were 

 immature. Three or four ends, however, have been secured, — 

 heads and tails of adults which are shown in Figs. 137 and 138. 

 It has been concluded that it is next to impossible to tease out an 

 adult worm from the fact that they all seem to be imperfect. One 

 may lift carefully the mucous membrane or a layer of muscular 

 tissue from a tangled mass which certainly has never been dis- 

 turbed or injured before, and examine the specimens as care- 

 fully as possible in situ, and it is almost impossible to see a 

 perfect end ; let alone a whole worm. In consequence one must 

 conclude that it is natural for the worm to disseminate its eggs 

 by throwing off the parted sections, as well as by the natural 

 exit from the uterus. ^ The one young specimen secured is 50 

 mm. — nearly two inches long — and the other more developed 

 one is about 70 mm. in length. Even though dissecting with 

 the greatest care and using a stereoscopic lens, on no occasion 

 have I been able to secure a piece of the body of greater length 

 than 75 mm. This is not to be wondered at when it is known 

 that the worm is only about .60 of a mm. wide; not more than 

 as thick as tissue paper. Its structure, too, seems to be very 

 delicate; breaking at the slightest touch, almost. The skin is 

 smooth and unarmed. It is difficult to state the length of an 



