3fi ProF. :M'lntosh's J^ntes /mm the 



by peristaltii' ooutr.actions to thp cardiac sac, whence it is 

 driven at iuti-rvals forward to the fominon hraiirhial vessels 

 and by the separate trunks to tlie tips of the brauchiro. It 

 returns by the same course and enters the lateral ventral 

 trunks, and passes to the ventral vessel, by which it is 

 distrii)nted to the collar and the body generally ^' {Hdsivell). 

 In Puiiiafoccnis the abdominal reunion possesses the peri- 

 intestinal vessel and a minute ventral trunk. Anteriorly 

 tlie former splits into a large dorsal vessel or cardiac sac 

 and about 16 smaller vessels, which run on the wall of the 

 alimentary canal. Further forward the peri-intestinal vessels 

 join the dor-sal trunk, thus making two main trunks, a large 

 dorsal and a small ventral. Then the dorsal bifurcates into 

 the two branchial, and so does the ventral, but Prof. Ilaswell 

 was uncertain wliether the latter communicated with the 

 former as in hjtpomatus. All the vessels possess a muscular 

 wall, and the blood in the majority is of a light green colour, 

 and contains certain clear oval bodies probably derived from 

 the epithelial lining of the vessels. 



A pair of thoracic glands exist iu this group as in the 

 SaWellidie. In Eupomatus and Serpula each. has the form of 

 a brown body with its long axis directed longitudinally, the 

 posterior part with thinner clearer walls and an anterior 

 dark brown folded part. No opening into the coelom was 

 made out by Prof. Haswell. In front the gland is continued 

 into the ciliated duct, which passes almost directly inward 

 to meet its fellow in the middle line, the common duct going 

 straight forward to open veutrally (dorsally) between the 

 bases of the branchise. The gland is lined by large, granular, 

 nucleated cells, each furnished with a flagelluui at its apex. 

 Ilaswell found the "true" segmental organs in all the 

 abdominal segments, viz., delicate pyriform sacs ciliated 

 internally, and ojcning externally on the sides of the seg- 

 ments by slit-like apertures having active cilia. No internal 

 aperture could be made out. In Eupomatus each in the 

 female contained a group of ova at various stages nj) fo the 

 fully developed -G'^f^. These segmental organs altei'uated 

 with the ovaries. Ju the males these sacs \iere always 

 empty. 



No feature is more distinctive of the Serpulids in contrast 

 with the Sabellids tlia-i the extreme transparency, thinness, 

 and minute serrations o the ho(»ks. As a rule, they approach 

 iu shape those of the Ampharctidaj rather than those of the 

 Sabilli(la3. The hard, smooth, calcareous nature of the tube 

 probably necessitates a s])ecial adajjtation of a mobile torus 

 with flexible hooks, the fiee edge of which is beset with a 



