THE SIMPLEST BRYOZOA. 117 



accorded a place among that heterogeneous assemblage, the "Worms," 

 and their closest relationship is undoubtedly with Phoronis, the 

 Sipunculid worms, and the Brachiopods. These agree in having 

 tentacles round the mouth ; an alimentary canal more or less U-shaped 

 the anus placed far to the front and often approximated to the 

 mouth ; nephridia (kidneys) reduced in number and rarely more than 

 a single pair ; the body unsegmented and often secreting a horny or 

 calcareous covering ; the nervous system greatly reduced ; parapodia 

 and setae absent. 



Two popular names are in use, "Corallines" and "Moss-polyps," 

 the latter being the translation of the term Bryozoa. 



Simplest of all the Bryozoa are the Pedicellinidce ; the typical 

 species, P. cernua (Pallas) grows luxuriantly in Jersey rock-pools, 

 clothing the stems of such algae as small Fucoids, the pink Corallina, 

 and the green Cladopliora. The individuals or zooids are stalked, 

 rising at short intervals along the creeping stem or stolon ; in form 

 they have a superficial resemblance to the Bell-animalcule (Vorticclla), 

 both having the shape of a wine-glass. Pedicellina is coy of full 

 expansion, and the ordinary illustrations of text-books never do it 

 justice ; fig. 10, pi. ix., drawn from a zooid just taken from a rock-pool, 

 gives a better though still inadequate idea of the graceful outward 

 curve of the tentacles under natural conditions. The stalk is con- 

 tractile and flexible and as we watch a group scarcely a moment passes 

 without we see one or another bob the body almost down to the base 

 of the stalk or maybe give a sweeping curtsey from side to side. At 

 another time the whole cluster may bow in unison a most comical 

 sight, and one that caused me instinctively to christen it the Bobbing 

 Coralline when first I made its acquaintance. 



The stalk is usually spinous, but all gradations to a perfectly 

 smooth condition are to be met with. 



The tentacles are solid and are arranged in a circlet around the rim 

 of the cup-shaped body. Such rim is the lophophore or tentacle-carrier. 

 The lophophore is not retractile as in those forms yet to be named, 

 but at will the tentacles can be folded inwards to form a rafter-like 

 roof to the vestibule or depression found in the centre of lophophore. 



A diaphragm separates the body from the stalk, and when, as some- 

 times happens, the former breaks off, it is not unfrequently replaced by 

 budding from the summit of the stalk. This tendency of the body to 

 break off is often very troublesome when one is endeavouring to stupefy 

 a colony preparatory to fixing. 



Within the depression (vestibule) enclosed by the ring of tentacles 

 are two openings, the mouth and the anus. Between the two rises a 

 small lobe, the epistome. Food is directed to the mouth by means of 



