NEW SPECIES OF PEEICH^TA. 



209 



limb of the U-shaped duct rests upon a finger-shaped pro- 

 longation (c) of the muscular bulb, or glandulo-museular sac, as 

 it is better to term it, which extends outwards between the two 

 lobes of the gland. In reality, as sections show, the penial duct 

 enters the " penial sac " or finger-shaped diverticulum about 

 halfway along its extent, though at first sight the communication 

 appears to be at the tip of the diverticulum. In other specimens 



Fig. 1. 



Diagram of a section across the glandulo-museular sac of the spermiducal gland 

 of P. Artwri (cf. PI. 16. fig. 4 c). The penis at rest. a. Penial duct. 

 b. Portion of the duct passing through the wall of the penial sac. c. Por- 

 tion of the duct lying free in the "penial sac." d. The penis itself. 

 e. " Atrium," or cavity of the muscular part of the glandulo-museular sac. 



Fig. 2. 



Similar diagram, showing penis protruded. Letters as in Fig. 1. The part of 

 the penial duet (c) has been pulled out by the protrusion of the penis. 



the recurrent limb of the penial duct (as in fig. 4 c) did not 

 extend more than halfway along this diverticulum, and this 



