94 MEMOIR V. 



totally different description from those the author had 

 previously observed in the Campanulariae, Plumulariae, and 

 genuine Sertularise of Lamarck, which are undoubted 

 Hydrse. This new animal, the Polyzoa, was subsequently 

 found in Sertularia Cuscuta, Spinosa, and Pustulosa, and 

 will, no doubt, be found in all the other species not fur- 

 nished with oviferous conceptacles, distinct in size, shape 

 and situation from the cells occupied by the animals, and 

 consequently in all the Serialaria of Lamarck. 



The Sertularia itnbricata of Adams being very imperfectly 

 observed and figured, has scarcely been acknowledged by 

 Naturalists as an animal production ; it is, in the harbour of 

 Cove, one of the most obvious and common species, 

 appearing as an amphibious parasite (PL I, f. 1.) on various 

 littoral Fuci, particularly F. serratus, creeping over their 

 surface by means of it's tubular ramifying roots, and 

 throwing off numerous flaccid irregularly branched shoots 

 to the length of from one inch to one and a half or more, 

 often so densely clustered as entirely to cover the Fuci on 

 which it grows ; the branches of this species go off in an 

 alternate order from the stem and branches, decreasing in 

 length from beneath upwards, and support at short intervals 

 clusters of oblong sessile vesicles,* imbricate or densely 

 compacted, and unilateral in regard to the part of the stem 

 on which they are respectively placed ; (f. 2,) these clusters 

 vary in the number of individuals, from three to near 

 twenty,with the intervals between the clusters at times short 

 and indistinct; the vesicles however are merely crowded 

 and have no connexion with each other, except through 

 the medium of the tubular stem on which they repose. 

 Wheh placed in sea water, the animals of this species shew 

 themselves more freely and in greater numbers than those 

 of any other submitted to examination. In their retracted 



'Vesicle is here used to sig:nify the cells actually occupied by the animals, 

 and not as applied to the true Sertulariae where it means a larger description of 

 cell or pod occupied by eggs only. 



