ON A NEW GENUS OF BIRD CESTODES. 141 



edge of the succeeding segment only to a moderate degree. 

 Then follow more or less triangular, but still somewhat 

 bell-like segments of relatively considerable length with a 

 delicate anterior and a wide posterior end, the latter pro- 

 jecting very markedly and overlapping the front of the 

 next proglottid. There is now a rather quick decrease in 

 the relative length, and an increase in breadth. It is in 

 this region that the genital glands become distinctly 

 recognised, their rudiments appearing in the more elongate 

 segments lying more anteriorly. By this time the bell- 

 shape has become lost and there is now very little over- 

 lapping of the now broad anterior portion of each joint by 

 the preceding one. The segments then increase very rapidly 

 in both diameters until the ripe segments are reached, the 

 measurements now remaining fairly constant, the length 

 being about 0*55 mm. and the breadth 0*75 mm. These 

 larger proglottids are only slightly connected with each 

 other. 



As mentioned previously, the specimen being unique and 

 in addition, being very small, no part could be sacrificed 

 for sectioning. Consequently very little can be said of the 

 histology and of the position of the excretory canals, 

 nerves, etc. 



The cuticle is about two micra in thickness. Below it 

 lie the small subcuticular cells. The longitudinal muscle 

 fibres are only moderately developed. No part of the 

 nervous system could be detected. The only portion of the 

 excretory system recognisable was seen in the region of 

 the developing genitalia. The vessels lie just laterally to 

 the vas deferens on the one side, and in a corresponding 

 situation on the other side. Their position is indicated in 

 the semidiagrammatic fig. 4. The parenchyma appears to 

 be finely granular, but this may not be natural. There are 

 in it numerous oval or rounded calcareous corpuscles from 



