548 R. C. PUNNETT. 



Rhynchocoelora to posterior end, and with pockets in the 

 CEsophageal region. Proboscis two-layered and with muscle 

 crosses. Excretory system with long duct and a single pair 

 of openings at the posterior end. No neurochord cells. Side 

 organ present just behind excretory pore. 



Micrella rufa, n. sp. 



Two specimens were obtained, one of which lacked the 

 anterior end. The perfect specimen was about 18 cm. long 

 when alive and extended, and about 2 — 3 mm. broad. In 

 colour it was of a bright vermilion, shading off into yellow 

 near the anterior end. Through the orange-coloured head 

 the brain showed bright red. In the intestinal region the gut 

 and its pockets showed brown through the body-wall. The 

 head was somewhat pointed in life, a feature which became 

 more marked as the animal essayed to burrow through the 

 bottom of the glass vessel which contained it. The larger 

 and imperfect specimen was probably, before the severance 

 of the anterior end, about twice the size of the above. 



The epithelium is crowded with unicellular glands, 

 which stain readily with picric acid. They are Avanting only 

 on the tip of the head, in the head slits and side organs, 

 on the ventral surface of the caudnl appendage, at the junc- 

 tion of the caudal appendage with the trunk, and in sundry 

 patches ventrally near the posterioi- end. The epithelium 

 rests on a fine basement membrane. Beneath this is an ex- 

 ceedingly delicate layer of circular muscle-fibrils. The large 

 cutis glands lie in the outer longitudinal muscle layer, and in 

 the oesophageal region they reach inwards as far as the 

 delicate nervous sheath surrounding the circular muscle layer 

 (fig. 2). Shortly after the oesophageal region they entirely 

 disappear. 



The muscular system in front of the brain consists 

 mainly of longitudinal fibres. Those directly surrounding 

 the rhynchodseum and cephalic vascular lacunre are sur- 

 rounded by a thin layer of circular muscle. Of the three 

 muscle layers in the oesophageal region, the inner longitudinal 



