2 NEPHTHYDnLE. 



A dorsal and a ventral blood-vessel (with a cardiac dilatation in front), and two 

 lateral trunks. 



Body-wall (Fig. 84) in section powerfully muscular, the dorsal longitudinal muscles 

 often fusing in the middle line and having an accessory band at the shelving edge. 



Nerve-area (see Fig. 37, p. 6) shaped like an inverted crown. Four conspicuous 

 neural canals — the inferior the larger, occur on each side of the median line (V. casca), 

 besides a variable number of others. To the exterior lie the tough limiting membrane, 

 the hypo derm, and the cuticle. 



ISO. 



E:S&. 



rvp. 



Fig. 35. — Magnified drawing of the segmental organ of Nephthys by Dr. Goodrich, co, ciliated organ ; iso, internal 

 end of the nephridium with solenocytes ; npc, nephridial canal ; np, nephridispore. 



The structure of the body- wall in Nephthys Hombergii as shown by Emery * does not 

 differ essentially from the foregoing. 



Segmental organs (Fig. 35) are long, slender tubes opening ventrally near the base 

 of the foot ; end blindly internally in a tuft of three to five branches with rows of soleno- 

 cytes (Fig. 36). An incomplete genital funnel in some passing into a sac in which are 

 waste products (Goodrich). F. H. Stewart 3 pointed out at St. Andrews the exact 



1 f Mitth. Zool. Stat. JSFeapel/ VII, p. 371, pi. 13. 



2 ' Ann. Nat. Hist./ ser. 7, vol. v, p. 161, pis. ii and iii, 1900. 



