250 BULLETIN OF THE BUREAU OF FISHERIES. 



4. Zoarium (in our species) simply and somewhat palmately branched from a creeping .stolon, the 



branches cylindrical, the ectocyst opaque and impregnated with earthy matter, zooecia connecting 



broadly with stalk at base Cylindroecidae. 



Zoarium creeping or rising and branching to form phytoid tufts, not impregnated with argillaceous 

 matter, the zooecia not communicating widely with the stalk or stolon 5. 



5. Expanded tentacles forming a perfect circle, gizzard present Vesiculariidae. 



Expanded tentacles not forming a perfect circle, as two of the number are bent outward, gizzard 



absent Valkeriidae. 



amily FLUSTRELLID^ Hincks, 1880. 



Zooecia immersed in a gelatinous layer from which rise tall chitinous spines. The orifice is dis- 

 tinctly bilabiate, "resembling exactly a common clasp purse. It is bounded above and below by 

 narrow horny ribs, which correspond with the metal clasps of the purse, and which are connected at 

 the sides much in the same way as the latter, so as to allow of their opening and closing ' ' (Hincks, 1880) . 



Genus FLUSTRELLA Gray, 1848. 

 Flustrella hispida (Fabricius). [PI. xxvn, fig. 72.] 



Fabricius 1780, p. 438 (Flustra hispida). 



Verrill and Smith 1874, p. 708 (Alcyonidium hispidum). 



Verrill 18790, p. 28. 



Whiteaves 1901, p. 114. 



Cornish 1907, p. 79. 



Zoarium forming a brownish incrustation which is hispid with the large spines, each of w'hich 

 arises from a swollen base, and which are arranged around the orifice and along the margin of the cells. 

 Zooecia very large, but their structure is not easily made out except in the young cells where the spines 

 are not yet developed. They are roughly six-sided, the surface smooth and flat, with the bilabiate 

 orifice slightly raised. The beauty of these colonies when the large lophophores are expanded "like a 

 blue mist, hovering as it were, over the masses of Flustrella on the weed" (Hincks, 1880), is very strik- 

 ing. They are not less beautiful when expanded for study under the microscope. 



Abundantly developed locally on the stems of Ascophyllum and Fucus at low water, occasionally 

 on stones and other objects, but not taken in the dredge. It is an eminently littoral species. 



Family ALCYONIDIID.E Hincks, 1880. 



Zoarium consisting of a gelatinous crust (sometimes more or less filled with earthy matter) or occa- 

 sionally rising into free cylindrical or expanded growths. Zooecia more or less closely united and more 

 or less immersed in the common crust, orifice not protected by external lips but closed merely by the 

 retraction of the tentacle sheath. 



Genus ALCYONIDIUM Lamouroux, 1821. 



KEY TO SPECIES. 



1. Zoarium impregnated with earthy matter parasiticum. 



Zoarium not containing argillaceous matter 2 . 



2. Zoarium covered with small conical papillae rising between the orifices of the zooecia, erect or 



encrusting hirsutum. 



Zoarium without such papilla? ? 



3. Zoarium encrusting mytili. 



Zoarium erect . 



