52 



Arenicolidae 



a massive Floridan example 330 mm. long, the shaft and rostrum 

 are practically in line, and merge into each other. The tip of 

 the rostrum, shown in Fig. 26 E, which represents the end of a newly- 



Fig. 23. A. glacialis. A, Young crotchet ; B, Later phase ; C, Latest phase of 

 growth found. 



formed, unused crotchet, soon wears away, leaving a rounded end 

 (Fig. 26 D). 



The crotchets of A. cristata are intermediate between those 



