STYELA. 



101 



position of the mouth in a large anal orifice, fringed 

 with a denticulated margin. The rectal portion is 

 short and not much diminished in calibre. 



The reproductive organs beset both sides of the 

 mantle, from which they jut prominently into the pallial 

 chamber. In S. tuberosa they are very numerous, and 

 are in the form of irregular, pyriform nodules, of a 

 bright orange colour, distributed without apparent 

 order, excepting that the attenuated end is mostly 

 directed upwards and towards the ventral margin. 



-y / 



A 



FIG. 60. Reproductive organs of Styela tuberosa. Magnified. 



These are the so-called ovaries, but they are reallv 



' / / 



compound bodies combining both the male and female 

 organs. The centre and larger portion of each is a 

 sac, in the walls of which the ova are developed ; and 

 the narrow extremity is produced into a short, nipple- 

 like oviduct, leading directly out of the sac. And 

 firmly attached around the base of each is a series of 

 small, oval vesicles, which are sunk in the substance 

 of the mantle, and which form for each sac a sort of 

 basal cup, within which they rest. These are the male 

 secreting organs, and their ducts, extremely delicate 



