856 
some others, are destroying the hardest lime 
‘stone ; the pholades are performing similar 
works, assigned by nature, on softer substan- 
ces, such as chalk, indurated clay, and wood, 
which in like manner are perforated by some 
solvent power ; not by the thin, fragile shells, 
that cover such animals, as some have erro- 
neously asserted, and is too generally credited. 
All these become fixed in their cells for life, 
for as they enter in the most minute state, 
the excavations are conic, with the small end 
outwards, so that the shells are as it were be- 
come enclosed. 
“Tt is most probably, the young of these, 
and other perforating ascidiz, that drill the 
small round holes so frequently observed on 
shells ; ané@ not the trochi, which are inca- 
pable of such works.” 
. We haye only to observe, that in the 
second paragraph, instead of class, Mr. 
Montague should have said genus. With 
respect to its class and its order, there 
has been no difference of opinion. 
To the genus solen are added the mi- 
nutus of Linnzus, a rare British species 
found burrowed in land limestone at 
Plymouth: the fragilis of Pulteney: the 
squamosus, the pinna and the novacula, 
nondescripts ; the latter in every respect 
like the siliqua, except in the hinge, 
which is furnished with one strong blunt 
curved tooth in each valve at one end, 
destitute of lateral-lamine: these teeth 
turn contrary ways, and when closed 
clasp or hook into each other. As the 
cultellus of Pennant is certainly not that 
of Linneus, it is here called antiquatus, 
the name given it by Solander in the 
Portland cabinet. Pennant, Da Costa, 
and Pulteney, have all erred in giving it 
but one toothin each valve; whereas in 
one valve it has two, into which the single 
tooth of the other closely locks ; but they 
are brittle, and easily destroyed. 
The alterations and additions in the 
genus tellina are numerous. The in- 
carnata of Pennant, the ferroensis of 
Pulteney, the radiata of Da Costa, and 
Lister, and the trifasciata of Donovan 
‘is called fervensis, its trivial name in 
Gmelin and Turton. The donacina of 
Linnzus is supposed to be the trifasciata 
of Pennant. The planata of the British 
Zoology, and Turton, the polita of 
Pulteney, &c. is called tenuis after Da 
Costa and Donovan. The carnaria of 
Pennant is supposed to be the incarnata 
of Linnzus. Ihe additions are, the lac- 
tea, the carnaria, and the inequivalvis 
of-Linneus : the remies ? and reticulata ? 
of Linneus, called fausta and proficua 
after Pulteney: the striata; and the fa- 
bula, of Gmelin: the squalida and leta 
NATURAL HISTORY. 
of Pulteney ; (depressa? and punicea of 
Gmelin: the maculata of Adams:) the 
totundata (undata? Pulteney) and the 
flexuosa, a variety of which is erroneous 
ly given by Donovan as the venus si- 
nuosa of Pennant. 
The additions to carduum are the acu- 
leatum and the medium of Linnzus: 
the exiguum (pygmzum of Donovan 
and Turton): the discors aarp pisi- 
formis?) the amnicum (tellina amnica 
of Gmelin, rivalis of the Linnzan Tran- 
sactions, &c.), and the lacustre (tellina 
lacustris of Gmelin, &c.): the rubrum 
and muricatulum described by Walker: 
the nodosum, the elongatum, and the ar- 
cuatum, nondescripts. ‘The animal of 
the corneum,ti:e amnicum and the lacus- 
tre, all fresh water species, is an ascidia 
witha, longtongue-shaped foot, by which 
it moves backwards by jerks.dilating and 
contracting it sieradtthe They are all 
viviparous, and are probably either an- 
drogynous or hermaphrodite, as all those 
which Mr. Montague dissected early in 
June contained perfect young. aistint 
Under the genus Jacira, several errors 
of former authors are corrected. Pen- 
nant has mistaken the true mactra stul- 
torum of Linnzus for his tellina radiata ; 
and has given for the mactra stultorum, 
a shell which has generally been sup- 
posed a variety of the solida, here made 
a new species, and called subtruncata. 
He has also taken a shell not known to 
Linneus for his venus borealis. It is 
the mactra listeri of Gmelin, &c., the te- 
lina plana of Donovan,, compressa of 
Pulteney’s catalogue, which latter name 
Mr. Montague adopts. The animal has 
“‘ two slender tubes placed near, together 
at the anteriour end; ene, about three 
inches long, is continually thrown about 
in search of food, such as insects, which 
may be seen passing up this transparent 
syphon, with the current of water it is 
continually taking in, and discharging at 
the shorter tube, placed nearer the hinge ; 
retaining only the nutritious matter : 
but it occasionally ejects the superabun- 
dant waters from both tubes.” | The 
mactra lutraria of Linneus, and the 
hians of Pulteney, and the Lin. Trans. 
having been confounded, the difference 
between them is clearly described by 
Mr. Montague. The animal of these 
two species is not atethys but an ascidia. 
The additions are the glauca of Dono. 
van, the dealbata (pellucida Gmel.), the 
boysii (alba of Mr. Wood. Lin. Trans. ), 
the triangularis, and the tenuis, nonde- 
scripts. 
