314 
Bibliographical Notices. 
boscis is outermost if the individual be uppermost in the roll ; thus 
all lie in the same direction, the proboscis outermost, as the Medusa 
escapes, from the next left behind. When the last remains in ad- 
hesion to the fleshy bulb, its proboscis projects outwards also. Thus 
the under surface of the embryo is always outwards, while a portion 
of the roll.” (p. 124.) 
“ Although by repeated, long, and painful observation, I have en- 
deavoured to learn the history of the Hydra tuba and the Medusa 
originating from it, my purpose has been but partially attained. I 
have selected many individuals, and I have chosen colonies of both, 
to discover whatever changes they should undergo. The hydra grew, 
it fed, it bred, its existence was long. The Medusa lived, it neither 
fed nor bred, its existence was infinitely shorter ; nor did it undergo 
the smallest change from the first moment of liberation for fifty-five 
days. Its life could not be protracted, on any occasion, beyond sixty 
days. Between the form and habits of these two animals there is not 
the smallest correspondence.” (p. 128.) 
We pass on to take a cursory notice of our author’s account of the 
Ascidian Zoophytes. 
Plates 43 and 44 illustrate Cellularia loriculata. “The hydra is 
minute, lively and active, almost transparent or dingy white ; it 
seldom protrudes from its dwelling, which has scarcely any percep- 
tible margin. When doing so, twelve is the usual number of tenta- 
cula displayed. Some have fourteen.” (p. 234.) Farre says that the 
tentacula are only ten in number. 
Cellularia reptans occupies plate 45. The hydra has twelve ten- 
tacula. 
Cellularia fastigiata is the subject of plate 46. The hydra has six- 
teen or eighteen tentacula. 
Cellularia ciliata forms the subject of a pretty plate, no. 47. “ None 
of the numerous tribe of Corallines can exceed the symmetry, ele- 
gance and beauty of this interesting product waving amidst the 
waters. The singularity of its parts and proportions seem to have 
originated wuth the vigorous efforts of a sportive organic nature.” 
(p. 239.) — To the vigorous enthusiasm which dictates such a passage, 
and there are many such in the volume, we owe the strength which 
supported our author in his long yet unwearied labours. — The hydra 
has from twelve to fourteen tentacula, and is remarkably vivacious. 
Cellularia avicularis is figured in plates 48 and 49. Of the latter 
we know not what to say : it does not please us, and is useless as a 
scientific drawing, however imposing it may look to the amateur or 
artist. Sir John has found the species only as a parasite on the 
Fhistra trvncata. “ A lively ascidian hydra with fourteen, fifteen, 
and, I believe, sometimes sixteen tentacula, inhabits the cells.” 
(p. 242.) 
'i'he bird’s-head processes or avicularia our author has seen on 
Cellularia ciliata, fastigiata, avicularis, and Flustra Murj'ayana. The 
obscurity which hangs over their function has not been lessened or 
removed by his researches ; and the conjecture which he throws out 
doubtingly that they may be i>arasitical seems to us altogether un- 
