94 



ANTHOZOA IIYDROIDA. 



I have a specimen of PI. cristata gathered in Cork Bay, and pre- 

 sented to me by J. V. Thompson, Esq., which is nearly three inches 

 in height, spreading laterally, the rachis divided in a regular dicho- 

 tomous manner, and rough or muricated on one side, wherever it is 

 naked of pinnae. The vesicles have from seven to nine crested ribs, 

 with a spinous dorsal keel. The roughness of the rachis is pro- 

 duced by the remains of the deciduous pinnae. I give a figure of 

 this specimen (Plate XXIV. fig. 1) as an additional proof that little 

 reliance can be placed on external habit as a character in deter- 

 mining the species of this order. 



Another variety imitates the habit of PI. pennatula. The cells in 

 it have a strong process on the distal side, which, springing from 

 near the middle, projects beyond the rim ; and the vesicles are larger 

 and more numerously ribbed than is usual (Fig. IG). This variety. 



Fig. 16. 









mm. 

 K 



vj 



which Mr. Couch has also noticed, appears to be a denizen of deep 

 water. My specimen was dredged in 30 fathoms, by Professor E. 

 Forbes, off the Isle of Mull. 



S. P. PENNATULA, pennated ; cells approximated^ cup-like 

 icith an unequally-crenated margin, supported on the under 

 side hy a lengthened incurred spinous process. G. Montagu. 



Plate XXII. Fig. 1, 2. 



Sertularia pennatula, Ellis and Soland. Zooph. t)6, tab. 7, fig. 1, 2. Fleming/ in Edin. 

 Phil. Journ. ii. 83. — Aglaophenia pennatula, Lamoiir. Cor. Flex. \Gly. A'ruiiss 



