CYSTICEKCUS TENUICOLLIS. 179 



in the intestines of the dog by the older authors, generally be- 

 longed to this species. For the determination of the species 

 the table of sizes given at the end of this section, and the 

 figures of the hooks on PL IT, figs. 7 9, are sufficient. 



The rather slender and less strongly curved hooks are re- 

 markable by the extraordinary length of the spine (Dorn, Tap, 

 Zahnfortsatz) in both series, and at the same time stand nearly 

 at a right angle, with the apex rather directed a little downwards. 

 The spine of the second series is, in its greatest length (see table 

 of hooks, p. 242, second series, d,a), nearly equal to the stem, which, 

 especially in the hooks of the second series, is very small, short, 

 weak, and slender. In both hooks, the stems are only about 

 0'02 mill, longer than the claws or sickles. 



In tolerably firm specimens the neck is drawn together 

 in spirits, so that it appears to form a strong curve or noose. 

 With this appearance it is difficult to see the justice of the 

 application of the name "tenuicollis" to this Tcenia, which 

 has been adopted for it by Dr. Moller and the committee 

 of examination in Copenhagen, even without taking into con- 

 sideration the fact that the name " Tcenia tenuicollis" has already 

 been employed for a Tcenia of the martens and polecats, the 

 Cysticercus belonging to which I have found in the liver of the 

 field-mouse. The marginal genital orifices are irregularly 

 alternate. The uterus is formed by a short, thick, dilated 

 median branch, from which a very few principal branches are given 

 off towards the sides. Of the latter I have counted as many as 

 eleven. They divide into numerous short diverticula, which are 

 at first undivided, and only fork near the margins of the seg- 

 ment, towards which they are generally directed perpendicularly, 

 In consequence of this arrangement, the uterus acquires the ap- 

 pearance of a garden-rake, at the upper and lower margins of 

 the segment. The different short diverticula, usually stand per- 

 pendicularly upon the last principal transverse branch, and at its 

 lower extremity even the stem of the uterus divides in the form 

 of teeth. I regard this form as very characteristic, and venture 

 from this to distinguish the segments of this Tcenia from those 

 of T. soliwn, T. Ccenurus, and T. serrata vera. It follows as a 

 matter of course, from what has been said, that the isolated seg- 

 ments, when thrown off (the proglottides), considerably exceed 

 the segments of the other large-hooked Tcenice of the dog in 

 size, and in this respect equal those of a Tcenia solium which 



