FAUNA OF THE CHESS AND GADE. 



415 



collections which present features of special interest. A short 

 description of the normal form of C. serrulatus will, however, be 

 given first, special attention being paid to structural features 

 which are liable to variation. 



Graceful in form, the female has slender and tapering 

 anterior antennas, which, reaching as far as the third cephalo- 

 thoracic segment, are only of moderate length; the eighth 

 segment of each antenna is shouldered, and the tenth, eleventh, 



Fig. 23. 



Fis. 24. 



Fig. 25. 



and twelfth (see fig. 21) are long and slender. A long and slender 

 abdomen (figs. 21 and 22) terminates in two long and slender 

 furcal segments, which are five times as long as they are wide. 

 The most remarkable feature, however, is a row of short spines 

 bordering the greater part of the outer edge of each furcal 

 segment. These are shown in figs. 21 and 22, and will be called 

 the " combs." Two short setae, without cilia, arise from the lower 

 part of each furcal segment, and from the end of each segment 

 extend four ciliated cilia of which the fourth or outermost is 

 short, the first or innermost somewhat longer, the third much 



