88 



BOYS AND GIRLS IN BIOLOGY. 



I think I had better take you inside and give you a look 

 at the little fellow himself before I describe his abode. 

 He has not sent us an "at home," and the door is 

 closed and barred; so we must be house-breakers for 

 once, and go in by force without an invitation. The 

 mussel fastens his doors together by four little straps, 

 and we must cut two of these before we can get in. If 

 you will hold the small end of the shell toward you and 

 the hinge upward (Figs. 88, 89), I will name the differ- 



Fig. 88. 



Upper or Dorsal Border. 



Lower or Ventral Border, 



ent directions, and then you can better understand 

 where the straps are fastened, and how the mussel lies 

 in the shell. The small end toward you is called the 

 back, or posterior end ; the large end in front of you 

 is called the front, or anterior end. The upper-hinged 



