82 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



is seen at 8, and a larval star-fish, called " Bipinnaria," 

 at 7, on fig. XII. 



Mr. H. C. Chadwick, the Curator of the Biological 

 Station, is our local authority on Echinodermata, and has 

 written a Memoir on Echinus and several other papers for 

 our series of volumes. 



VERMES. 



(Figs. IX. and X.) 



There are veiy many kinds of marine worms. Some 

 are microscopic, some are parasitic in or on other animals, 

 and some are lowly developed and very sluggish, and 

 inhabit mud and decaying sea-weeds, such as species of 

 Tetrastemma and Lineus, usually to be seen in our tanks. 

 We shall only illustrate here a few of the higher forms, 

 which are of fair size, of active habits, and are provided with 

 feet or bristles on the segments of the body. These higher 

 bristle-bearing marine worms, or " Annelids," fall into 

 two sets — the Errantia, those that wander freely, creeping 

 over rocks and sea-weeds and under stones, and the Seden- 

 taria, those that inhabit tubes either fixed or moveable. 

 Amongst the commonest of our Errant Annelids are the 

 Nereis pelagica (1) and the Polynoe (Lepidonotus 

 squamatus) (2) shown in fig. IX. No. 3 on the same figure 

 is a sedentary Annelid, the little Sjrirorbis borealis, which 

 makes small spirally coiled white calcareous tubes on the 

 surface of stones, dead shells, and coarse sea-weeds all 

 round our shores. The tube alone looks like a little shell, 

 but it is a worm which builds it, lives in it, and which 

 while alive can protrude from the opening a beautiful 

 plume of delicate branched tentacles as is seen in the 



