Mr. P. H. Gosse on new or little-known Marine Animals, 35 



vibratile cilia. These fans are very deciduous, for, in captivity, 

 I have seen the animals voluntarily throw off in succession more 

 than a dozen of the stems, separating them at the base : probably 

 they are renewable, as I know to be the case, from repeated 

 observations, in Sabella. 



Segments about thirty-three ; nearly equal, except that they 

 diminish rapidly at the posterior extremity, tapering somewhat 

 abruptly to a blunt point. All but the last two are furnished 

 with graduated pencils of bristles, about eight or ten in each 

 pencil. In those of the anterior segments the bristles are of 

 two forms (fig. 27), the shorter consisting of a slender, acutely- 

 pointed stem, which is dilated near the tip into an oval plate, 

 through the centre of which the stem passes ; the longer ones 

 are of essentially the same structure, but the dilatation is gra- 

 dual and elongate, and therefore blade-like or lanceolate. Both 

 kinds end in finely-drawn points, which are much curved. To- 

 wards the hinder part of the body all the bristles take the latter 

 form. 



The animal throws off at will a transparent gelatinous mem- 

 brane, which forms a tube just large enough to hold its body, 

 and the sides of which are pushed out by the bristles during 

 their movements. 



Length i an inch ; colour greenish-white. 



I have named this species after Dr. George Johnston, who 

 may be called the father of our marine invertebrate zoology. It 

 is the most common of the three at "Weymouth, being found 

 abundantly in shells and stones, dense sea-weeds, &c., from tide- 

 marks and deep water. 



Class POLYZOA. 



Order Infundibulata. Fam. Vesiculariad^. 



Genus Nolella (mihi). 



Cells erect, subcylindrical, springing singly, but closely, from 

 an undefined polymorphous incrusting mat ; tentacles eighteen, 

 forming a bell. Name from nola, a little bell. 



N. stipata (mihi). Plate IV. fig. 29. 



Cells about ygth of an inch long, whitish, sub-opaque. 



I found this species numerous in mats on the fronds of Plujl- 

 lophora rubens, dredged between the Abergavenny and Portland 

 Breakwater, in Weymouth Bay. It is very near Bowerbankia, 

 but the number of its tentacles distinguishes it from all recog- 

 nized genera, except Avenella (Dalyell), from which, however, it 



3* 



