CALMA GLAUCOIDES 447 



suggests a zymogenic character for the latter. The cell of 

 fig. 6 is on the metabolic down-grade ; the more centrally 

 placed secretion has been brought into solution, and the 

 streaming enzyme from the nucleus has also attacked the 

 periphery. The necessity of means of storage must be present 

 in all organisms depending on a precarious food supply, but 

 a peculiar spatial relationship exists in Calma between gut and 

 gonad, which makes it advisable to postpone the discussion of 

 the utility of these cells until after the reproductive system has 

 been described. 



The Nervous System (fig. 7) resembles closely that of 

 Facelina and other Aeolids with uniseriate radulae. The 

 following points are to be noted : 



(1) The large dorsal ganglia (cp.g.) contain the cerebral 



centres and all the ganglionic elements of the visceral 

 commissure. The short unbeaded visceral loop (v.l.) 

 gives but one visceral nerve which sends a branch to the 

 gastro-oesophageal anastomosis and continues into the 

 reno-cardiac plexus, and probably the gonad. 



(2) The rest of the reproductive system is innervated from 



a stout nerve (g.n.) arising from the right dorso-pedal 

 connective. This nerve consists of fibres derived chiefly 

 from the dorsal ganglion, and some pedal fibres. 



(3) There are large rhinophorial ganglia (rh.g.), and the optic 



ganglia {o.g.) are also outside the dorsal mass. 



(4) The parapedal commissure (pp.c.) is distinct from the 



pedal. 



(5) The eyes and statocysts (ot.) are placed, as in most 



x\eolididae, dorso-laterally in the angle between the 



pedal and dorsal ganglia. 

 The vascular system does not call for special description, and 

 the renal and pericardial coelomic spaces have, as Hecht (loc. 

 cit.) has shown, the normal relations and openings, but the 

 kidney is unusual in being a simple dorsal sac extending back- 

 ward from the pericardium to the level of the sixth or seventh 

 ceratal groups. 



li 2 



