STROPHOlVffiNIA AGASSIZI. 233 



beneath the pharynx the other imbedded in the diffuse saUvary glands passes 

 dorsal to the gut. At one or two points between this region and the brain nerves 

 arise from the connectives and form seemingly either dorsal commissures or a 

 very delicate network which it is impossible to trace from sections. 



In the posterior end of the body the lateral and ventral gangUa continue 

 to hold the usual positions and to be united by connectives and commissures 

 at iairly regular intervals. A short distance behind the level of the posterior 

 end of the pericardium both of these ganghonic cords enlarge considerably and 

 are united by one especially heavy pair of connectives as may be seen (Plate 1, 

 fig. 5). Slightly in front of this another pair occurs of about half the diameter 

 of the one beliind. The remainder in this region present the usual slender 

 appearance and are sometimes difficult to follow. In many cases they give off 

 delicate fibres that pass to the body wall where they probably supply sense 

 organs or are distributed to the somatic muscles. 



The suprarectal commissure is long (Plate 2, fig. 6), not especially heavy 

 and gives rise to a, few very small nerves that pass at once to the rectal wall 

 where they spread out fan-like and disappear from view among the muscle 

 fibres. Here and there are indications of a nervous network over the surface 

 of the rectum but from sections neither its origin nor its configuration has 

 been determined. 



The ventral commissures in the posterior end of the body are without excep- 

 tion of large size and are readily followed. In a few cases fibres have been 

 seen to leave them and pass into the ventral body wall, especially lateral to the 

 ventral furrow; and in one specimen (Plate 1, fig. 5), one such nerve unites 

 with the ventral ganglion and originates a fibre, in the nature of a connective 

 that follows the body wall and resting upon the accessory reproductive organs, 

 passes dorsally and unites with the lateral cord. 



The pedal cords, behind the last connective, give rise to a very few nerves 

 that disappear at once in the mass of muscle surrounding the cloacal wall at 

 this point. The lateral ganglia likewise are continued behind the last connective 

 as a heavy cord apparently distributed in large measure to the cloacal wall 

 though some branches may pass to the neighboring body wall. 



As in the case of Proneomenia vagans this species is in possession of two 

 dorso-terminal sense organs (Plate 1, fig. 5). Both present the same as well as 

 the customary appearance, but their innervation is unique. In Proneomenia 

 hawaiiensis a nerve leaves the exact centre of the suprarectal commissure and 

 pursuing its course along the mid line passes into the base of the single terminal 



