WAGENER, ON GYRODACTYLUS ELEGANS. 203 



the loops, proceed towards the caudal disc. In the latter part, 

 between the fourth and fifth hooklets on each side, and close 

 to the border, are two very large, active, ciliary tags. Whose 

 free apices point directly inwards. It may also be noticed 

 that an opening exists at this spot, on the somewhat swollen 

 margin of the disc. Whether this opening communicates 

 with a csecal cavity or a canal remains undetermined. 



The two pairs of vessels in their covirse towards the head 

 make two principal curves, by which the space circumscribed 

 by the vessels is subdivided into three portions. 



The lowermost of these divisions extends from the confluence 

 of the vessels to the lower border of the testis. At this point 

 the vessels bend suddenly outwards, but with a rapid curve 

 again approach each other on a level with the lower border of the 

 uterus, then again bend a little outwards, and with a gently 

 undulating course run immediately on the pharynx, on whose 

 sides they continue visible as far as the oral orifice, after 

 Avhich they gradually diminish in size until they are lost to 

 sight. 



On the spot where the vessels override the upper border of 

 the intestine, a couple of minute ramuscules are given off on 

 the inner side. Another far larger branch curves outwards, 

 and pursues a winding course upwards and downwards 

 through a mass of cells corresponding in form to unicellular 

 glands. 



These unicellular glands, as they may be termed, are situated 

 in each side of the head, on either side, constituted of a superior 

 and an inferior collection. The upper is the smaller, and 

 consists of from six to twelve retort- shaped corpuscles, some 

 of which always contain a transparent nucleus, together with 

 a corresponding opaque nucleolus. 



The inferior and larger glandular mass consists of from 

 eight to twelve far larger cells. Each of these presents a 

 clear nucleus and an opaque nucleolus, which, as in the 

 superior glandular mass, lies in the midst of a more or less 

 brownish, opaque, fine granular substance, with which the 

 entire cell is filled. 



From each of these bodies proceeds a finer or coarser 

 filament, filled with a similar material, towards the cephalic 

 lobe on the same side, at the border of which it terminates. 

 These filaments are not of uniform diameter throughout, 

 having here and there enlargements upon them. The 

 glandular bodies themselves are placed on the dorsal side of 

 the animal; but the filaments, united into a brownish sub- 

 spiral bundle, run on the ventral aspect. In the cephalic 

 lobe each filament becomes much dilated. Its course may 



