274 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



animal, and especially its anterior end, be subjected to 

 pressure, the yellow pigment seems to become diffused 

 through the whole skin, and the yellow granules in the 

 cells mostly disappear. Some of the pigment also exudes 

 into the water. Later such a compressed anterior end 

 becomes green, and this pigment resists solution in alcohol. 

 The skin also contains numerous mucus-forming cells, by 

 the activity of which the enveloping tube is formed. A 

 specimen which was deprived of its tube was found 

 twelve hours afterwards enclosed in an elongate mass of 

 mucus formed by the epidermis. 



The secondary annulation of the skin, which corres- 

 ponds to that of the adult, is shown in many post-larval 

 stages, except in the first two or three segments, where 

 the annuli are less clearly indicated. The metastomial 

 grooves are only faintly seen. They unite just behind the 

 middle of the achaetous segment, and are there continuous 

 with a shallow mid-ventral groove which marks the 

 position of the ventral nerve cord. 



The mouth is a crescentic or semi-circular aperture 

 at the anterior ventral edge of the peristomium (fig. 58). 

 The pharynx is protrusible, and bears small papillae. It 

 leads into the ciliated oesophagus, which bears the two 

 glands, each of which is a simple finger-shaped outgrowth 

 of the gut, '25 — -'45 mm. long, directed forwards, and 

 showing in its posterior portion three or four slight 

 internal ridges which are the precursors of the larger 

 septa found in the glands of adults. The secretion of the 

 glands is already present in the form of droplets, some of 

 which are still in the glands, while others are in the 

 posterior portion of the oesophagus. The stomach is 

 marked by elongate oval areas, between which are blood- 

 vessels. Chlorogogen cells are present, but are only dis- 

 tinguishable along the margin of the blood-vessels, and 



