NORTHUMBERLAND AND DURHAM lOl 



On CoralUna officinalis^ in a rock-pool, between tide-marks, 

 Cullercoats. 



Only one S2:)ecimen has yet occurred to me of this interesting 

 little zoophyte, which may readily escape observation on account 

 of its diminutive size. It was observed on a branch of CoralUna 

 officinalis that had remained for awhile in a glass of sea-water, in 

 the autumn of 1853. The pools where it was obtained have 

 been searched several times since for additional specimens, but 

 without success. I am happy, however, to find that the species 

 was also found in the same year by Mr. Busk, at Felixstowe, in 

 Suffolk. The Cullercoats specimen, which lived with me several 

 days, was sluggish, holding itself always in a curved position, as 

 represented in the figure. The body is nearly cylindrical, taper- 

 ing slightly towards the upper part, where it enlarges into a 

 distinct head, having two rows of tentacles placed upon it. The 

 mouth is tubular and prominent: the ujDper tentacles, which 

 surround the mouth, are short and capitate, and generally curved 

 inwards: the lower tentacles form a radiating circle near the 

 base of the head; they are moderately stout, and taper slightly 

 towards the extremity, which scarcely shows any terminal swell- 

 ing, unless when much contracted. Tlie enlarged head of the 

 upper tentacles is permanent, and when highly magnified is seen 

 to have a congeries of little tubercles, which probably contain 

 thread cells. The embryology is unknown. 



Mr. Peach has described, in the "Annals of Natural History" 

 for August, 1856, the change of a zoophyte somewhat similar 

 to this into a naked-eyed Medusa. That gentleman's observations 

 lead him to conclude that this change was a complete metamor- 

 phosis, and not a reproduction by gemmation, as is usually the 

 case, though the exact point of transition does not aj)pear to have 

 been observed. 



Names given to genera in this family must be considered pro- 

 visional, and subject to revision if the zoophyte should after- 

 wards prove to be the transition state of something already 

 known. At present this genus has as good a claim to recogni- 

 tion as Clava, and some of its nearest allies. 



