444 DR JOHN RENNIE AND MR ALEXANDER REID ON 
The scolex is of distinctive appearance, being lone, blunt, and of almost uniform 
width, measuring 2 mm. by ‘75 mm. in extent. There is a pair of shallow, widely 
gaping suckers, dorso-ventrally placed, extending the whole length, and open at both 
ends (fig. 5). 
The mature segments are rectangular in form, with slightly undulating margin. 
In the specimen 42 mm. long, the largest, which were terminal, measured *61 mm. long 
by 1°04 mm. broad. They are also relatively thick, measuring in section 61 mm. 
dorso-ventrally. 
The cuticula and sub-cuticula are of typical appearance. Beneath the sub-cuticula 
are the yolk follicles. These are very numerous, and in many sections, e.g. those at 
the level of the ovary, they form a practically continuous band. The individual yolk 
cells, which vary in form, measure on an average about ‘014 mm. by ‘017 mm. 
The shape of the ovary presents no unusual features. In a section at the level of 
its junction with the yolk ducts it has the form of a transverse band. Posteriorly to 
this it appears as a pair of detached, more or less rounded, and thicker masses. The 
ovarian cells measure ‘017 mm. by ‘01 mm. 
The uterus consists of a few close coils which wind dorso-ventrally, so that in 
section it usually has the appearance of an almost complete circle. The shelled ova 
measure ‘052 mm. by ‘041 mm. 
The testis follicles, which occupy the greater part of the central area of the 
proglottis, measure in their greatest dimensions (034 mm. by ‘052 mm. 
There is a well-developed inner layer of longitudinal muscles; the dorso-ventral 
muscles are also well marked. 
The longitudinal nerve cords are extremely ill-defined and weak, although 
relatively large. They are placed slightly less than one-fourth of the width of the 
proglottis from the margin, and are slightly nearer to the ventral than the dorsal 
surface. 
The central longitudinal excretory canals can be made out only in places. They 
are placed at the extreme lateral margin of the central layer, next to the longitudinal 
muscles, but, as they frequently cannot be traced in serial sections, they probably 
anastomose a good deal. Peripheral canals are present just exterior to the yolk 
follicles. These are most clearly visible at the lateral margins, where two or three 
frequently occur close together. 
This form differs in most particulars from all the hitherto described species of the 
group to which it belongs, and we have therefore classed it as new, naming it Dubothrio- 
cephalus coats:. It is an interesting fact that two new species should have been 
obtained from Stenorhynchus by the Scottish Expedition, and that D. quadratus, 
the only form hitherto described from this host, should not have been found. 
