336 C. ROUSSELET ON PEROPHORA LISTERI. 



their growtli by gemmation on the creeping stem, similar to 

 the budding of fresh-water polyzoa. 



I have noticed that when an old animal dies a new bud is . 

 frequently formed inside the old tunic, which forms a ready- 

 made house to the growing bud. 



I trust that these few notes will enable those not already 

 acquainted with this interesting group of animals, to better 

 understand their structure when examining the living examples 

 commonly found everywhere on our coast, but if they are fortu- 

 nate enough to come across the somewhat rare species described 

 in this paper, I think they will agree with me, that there are 

 few more beautiful sights in microscopical life than is Perophora 

 Listeri. 



EXPLANATION OP PLATE XXY. 



Fig. 1. Perophora Listeri, a single animal on its peduncle, side 



view, x 30. 

 „ 2. The same, front view, looking down upon the oral orifice, and 



showing the branchial sac snspended freely in the atrial 



chamber, being attached to the tunic only on the ventral side 



and around the mouth. 

 „ 3. Group of Perophora x 6. 

 „ 4. Diagrammatic transverse section through Perophora. aa. Atrial 



chamber, cc. Cavity of branchial sac. tt. Test or 1st tnnic. 



mm. Mantle or 2nd tunic. pp. Peritoneum or 3rd tunic. 



bb. Proper wall of perforated branchial sac. e. Endostyle. 



