126 MUNSON. [Vol. XV. 



both in longitudinal and in transverse section of the tube, 

 are cut transversely or obliquely, longitudinal sections of the 

 fibers rarely appearing. The cause of this becomes plain when 

 the tube is slit open, spread out on a slide, and stained in toto. 

 Those large sac-like swellings previously mentioned have been 

 selected for this purpose. Killed in picro-sulphuric, and hard- 

 ened in alcohol, the wall of the greatly expanded tube remains 

 sufficiently tough to allow its removal from the mass of con- 

 tained eggs ; and its elasticity is sufficiently destroyed to pre- 

 vent its return to its normal contracted state after removal of 

 the eggs. Such a preparation, stained with the Biondi-Ehrlich 

 mixture, shows the following arrangement of the fibers. Very 

 symmetrically arranged oval areas are observed where no fibers 

 are present. Around these areas the fibers run parallel to one 

 another, constituting a sort of striated rim or border around the 

 area. Between these areas with the encircling muscle fibers 

 the fibers cross and intercross, some becoming continuous with 

 the encircling fibers of one area, others passing around another 

 area, and so on. The beginning and the end of these fibers 

 could not be made out. They seem to branch freely and have 

 nuclei imbedded in their substance. 



The oval areas are due to the characteristic arrangement of 

 the muscle fibers ; and this arrangement is the expression of 

 the regularly arranged follicles in the adult ovary of Limulus. 

 The oval areas themselves are the follicles which have become 

 obliterated through the stretching of the walls of the ova- 

 rian tubes. That the muscle fibers retain this characteristic 

 arrangement in the wall of the tube, when greatly extended, is 

 perhaps sufficient evidence that these are permanent features 

 of the muscle coat, and not, as might be supposed, transient 

 features due to displacement by developing eggs and likely to 

 occur at any point where an egg might chance to develop. In 

 the adult ovary it is this arrangement of the muscle fibers which 

 determines the position and makes possible the characteristic 

 follicles of Limulus. Something more concerning the origin of 

 this arrangement and the part which the growing egg may have 

 in its production is to be considered in connection with the 

 development of the ovary. 



