,
=
ECONOMY 0E'THE - BODY—I
3211
j
7
varying degrees of use and renewal and partly to the fusion
-
of, some ofthe roots together. As they are seldom planted
in socket$,_but merely apposed or ankylosed to the jaw boues,
they are readin lost and as
Frequently,
'owing, to Some disturban€e of the -tisSuèsyih the
several nidiments may lse together to* form »veompoâte
Ï
teeth, andthey are often absent altogèthetu
:,
'
,
In additionto the “, front ” teeth, which may b'e‘preeeded
.
'in deep—sea forms by
milk ” teeth, there are pharÿngeàl
or gill teeth on the last branchiàl‘ archl where the
:
narrows towards the gullet_. These are of a similar nature
but are usually of 4a stronger build'thâh the jàwteethi IÎ1
the majority Of species there
ÉcheWing' of the materials,
_i
the sh sirhplybblt thefood asifastas they Can and they have
;
no -Salivary glands.’ But in the ÏLUng—shes and perhaps
‘
the Mullets Some
masticatiOn seems to take place.
'
between :gùllet or œsOphàgus' and.
stomach_ _îisf n0t well—marked fin_ __shès. In the
indeed,stomach
hinder
,
,
endÿof‘wloh’
‘
,
31' d);
'
-
: -,
…
commumcatswth
cerrectJudgmgfromtheadultstructure ':ThéîËdéïëlèÿîäï "ç,
mm mm hwthtthmhtbgmh
Sometimes the cul-deasae i‘sf
lÉ '
;
distensible, as in Amih0_dytesï and the Tràchyptétidsç In
"
:
it eXtends backwards almost to the tail, and in a
'
“_ heighbouring form, L0photes, it seems to have obtained a
Communication with the "eXterior.
j
'
,
beginning, therefore, the stOmach has been-more
1
.'
:
Ÿiareta1mngorgan or crop than
Ï [
coat is
-develOPed, that it
forms
1egulargrzzard
is foundmthe
_
and in? the Mullët”sf;
 ;Ï
we“ ,
extreme, } as1mplestralghttube?ï !:f._,
,
{ fîîf’r ?
These examples illustrate thelowstagebfffdevelopientïæ