116 



crease iQ size and distance frora each other. They theu continue of 

 the šame relative size and distance apart (2 lines) till within about 

 lialf an inch of the posterior extreniity, wlien they agaiu, hovrever, 

 become smaller and niore closely approximated. In all the four 

 specimens which I examined, the rings were twenty-seven in nnmber, 

 and where largest, projected nearly half a hne from the surface of 

 the body. 



In the fresh specimen, when examined witb a pocket lens, the ex- 

 terior of the rings appeared mottled with faint •cThite-coloured spots. 

 They \vere and still are quite opaąue, whereas the intervening tissue 

 is s"o thin and transparent, that the internal -s-iscera can be seen 

 through it. A number of white bands or cords appear to connect 

 one ring \vith another ; the bands are largest m the lateral and dorsal 

 regions. A dark-coloured hne extends along the back throughout 

 the whole length of the body : this, as I shall afterwards have 

 occasion to show, is the digestive canal. 



On the under surface, in the centre and near to the anterior margin 

 of the head, which is shghtly flattened from before backwards, is a 

 round foramen, the mouth. " On either side of this opening are two 

 Jepressions, ecjuldistant from each other, each containing a prehen- 

 sile hooklet of a bright yellow colour. These hooklets in shape 

 closely resemble a cat's claw, which can be extended and retracted at 

 pleasnre, and when completely dra\vn in, the points of them can be 

 neither seen nor felt. The ohtuse posterior estremity has a deep 

 cleft across it, and on its luuler surface are two openings, one in 

 front of the other : the anterior is the entrauce to the vagina, the 

 posterior the anai aperture. 



Anatomy of the Entozoon. 



Parietės. — The whole body is invested with a delicate, smooth, 

 transparent cuticle, which can be readily detachcd by slight mace- 

 ration. Beneath the cuticle are tvvo laycrs of striated muscular 

 fibrcs (PI. XLYII. fig. 13), a vertical antį a transrerse layer ; — the 

 longitudinal fibres are by far the most developed ; — the circular are 

 in some places entirely wanting. The projecting rings, on the other 

 hand, are not composed of striated muscular fibres, but consist of 

 fibro-areolar tissue. They seem to serve as fixcd points of action 

 for the longitudinal museles ; appearing to supply, in fact, the place 

 of a hard skeleton. The interior of the abdominal cavity is liued 

 by a fine transparent menibranc, on \>hich I thought I could detect 

 a single layer of delicate ])avement epithelium. 



Digestive System. — The alimentary canal, in couseąuence of its 

 peculiar dark saiFron tint, is readily" traceable from its commence- 

 ment to its termination. It begins at the mouth, and runs in an 

 almost perfectly straight line to the opposite extremity of the body, 

 terminating, as was before mentioned, immediatcly behind the orifice 

 of the vagina (PI. XLVI. fig. 4, a). Close to its commencement 

 it is of the diameter of a fine crow-quill, and may be said to continue 

 of nearlv the šame size throughout its vvhole course. It lies directly 



