EXPLANATION OF THE PLATES. 393 



Kg. 



spines, of which there is a corresponding row on 

 the opposite side ; (c), dorsal tnft. 



27. Pollicipes polymeria; a segment of the sixth cirrus, 



showing the arrangement of the spines ; (a), main 

 anterior spines, of which there is a corresponding 

 row on the opposite side ; (6 b) y calcareous shields 

 on the dorsal surfaces, with tufts of fine spines 

 near their upper edges. 



28. Alepas comuta ; sixth cirrus of; (a) basal portion of 



one ramus, consisting of numerous segments ; 

 (&), the other and almost rudimentary ramus. 



29. Pcecilasmafssa; segments of the sixth cirrus, showing 



the arrangement of the spines; (a), anterior spines ; 

 (<?), dorsal tufts. 



