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• :io:t

(s>%?

.•ofessor
was made possible for me to ~o to . C, in

summer of 1902, and while there, I it his !

to collect material for 3ad-s]

Lsh, . found nting

e^s, and, wishing bo bake up the i this fis ,

ite.

..ions
-
summers -water n

hand, - - iculties .

ere

L

reau of Fisheries ort, N. C.

. .^oner, Ho .

excellei
- . To the Director, Dr.
ms for many helpful e i . >ns,
further work vas done in -

I

of the To Iniversitj . Pr< ^essor ". '.

L for the inti i

ion, I t!s( . E. A.

il "rave for advice in overcomi
L £ Iculties of eg

? s with int

the upper end of t
with forceps \
acope. If these were i

. L - .vith

scissors :),

ave tis-

althou rarely sui a second o

si ly, -sis

in removi
'l.G o ;- ii of a series of cys an
. - -- a. is a lone, slow, and laborious t
as much the result of chance as of skill an. .ge.

A variety o : . oil

drops ^

■
enoerg, si -acfefcic,

all ga1 - it to

s . . sh

- . . Tor later stages, Wilson's
Worcester's fluids. This latter is one of the best flui

tclC : e .It

is composed of !

in this from

ith Iodin.

-

i

s was ver ... todcrms,

Iks

. ie processes fr

in Perenstj ' s J
soft /oiks, w - - . s kill-

, hence t [Uick3

as po ! s i L .

,ffin, it, is
necessary to :
Borax- ...mutes, t

.

- -S.

m& sections cut

...
it iful

exclusiv<

5
HABI

;
■
f 'So) reports that _S. arp;yrosticus as

t I'Xt

S. :- ; icirc-.', T c l..;^e ■. Dory-

ichthys 50 up the rive ' rts

, in quie
jottoms, Zostera

- - - -

t in cons
It may be well to note thai olor of these fis

es with the sea- weed! y found.

.S. f 1 -■ - - - ss

'ut a _ __ .

S. fu.scu:.: is ordinaril ;i color,

(al speci
sea- wee., were brick-red in color a;.
to he speci e £ .

3 FI . ' ' .

The followi - its

the 1 ab o r at o r: o f
Lor J .

ries . .

witness

Wnen m;

ted to them and t Lr a iti

fu 1 1 s . t .

A £ to gi

dis . :e of

s in ■' ovi co-

first i

— -

flat in
l - cone v/i .

projecting skin-covered ho- sex-

these fli m into f<

e Lc £

- . . [ fi . . a \

i
like an italic latter f_. Then the; s t each

other, their

B - ,

: i
-

snout cares;: ; .

Le respon come so exciti .

a

ii c k
flash the sexual em
fishes separate to begin again in a

consists in 'ii s intert L ._

r*sed
•-:. - face. Thus

ict into . . Their bodies touc Lac-

«s; i ' . -'.is;

sterior r
the way from the anus to . , L open-

ings, ilia, or t

female, is, _nt of contact of their ho .

st into the button-hole- sh i hor

i a

the pouc 'ertilis

it .

ant _ . ouch,

into the j encj , abou

curious
vertically, and, resting his c

tha bail on :he floor o ■ .w c

forwar Lsts hi body spirally fr

This is repeated until fc]
posterior end c I do not thi

■re ring this about,

]

i . vidence of cili-

ary action, Secti from pi sal and ven-r

tral parts of t . f

fluids
v i ilia.

Then for some

- e, L U.

... . i a

floor c aquarium. Li position is r

nove--
menis, lasti . ...

The processes above
is fill e.'.,

■ , ■ •

-iiov/s, 10:15; 1^:34;
10:39, at whi
pouc LI: 06, . at

: 45 and 11 : 30, i
lobe v I sfer taxes

nd a]

i

La font .

It does not - t ls-

ferred at once; first, because - used

Ls in the poui
place, bee i such

. alf fii Le

■e not infrequ
these processes mi-

.
one-] air hours (the extent or my observations). On
this . ■

" two of Lternati at no

I

had prot :ts.

7or coition to tak the

fishes should he nearl i . size. J.e,

paire< - .

i
out a parallel i - o rer vertebrates. Jordan ( 'Jj.)

records for Di y

hi s
caress. . ' c.iAthe

spread fins, swi s them v/i

snouts. fc

Invert ehr ■ate s . R&cavitza ( '94) h

of Octopus vulgaris st .All

acts see -o excit e

The ■■
i

- isist of

of two, or of ,

As not ] be one, two, or even

iposits i si . -.es,

Ld
narily the se
to set fre

ttchin ie given i v s

i
These ;

ird-li--; ion oft'. , same i

ien
- ttle

The

out in
out injur i .

relieved c Llowi

0 se, stri a me, died

after taking - Lot. W :n the

:>r forty- ' ours, they bee

j it Tooth at be-

. necessary to kill the he flaps

of skin before one can extract the •

The fishes vary in size. The extreme* in eg •, bearing
males of S. floridae I have found to be 4,5 to 8.9 inch-,
in females 3 to 8.4 incr.es. As a general ever the

j. e s ar e s er ,

Foot-note to p,

A review of of Aristotle

to the present, c characters, br Its,

onic structu s rancha with

certain observations of my own, ii

- --
] I ,

I,

- s fish is of f ir L size
having a diameter of about 1 . It possesses

a thi

one- twelfth homogeneous oil immersion lens, shows no structure
jtions, but in surface views presents, when stai

Mice,

, but if left on
offer no obstruction to imb« in process

es. The e£fjs are formed in ovaries which, viewed from
ent the ordinary Y shaped structure common
to the Teleosts. These ovaries are two tubular or
situated in the posterior dorsal portion of the body cav-
and are confluent behind to form the short oviduct
opens ■_ or lip o

/

However when ont of the ovaries is sections , a
very interesting structure is rr . u u i

wise throughout the whole extent of the ovary is ara
situat two-thirds or the distance fr

or? in succession to form a spiral
phe, the outermost eg b
the olde; . - .

creases in size and cr r with t

raphe closely to one side of the tube. In the ovaries of
:s, two or three £
. i

' .
mously distend the ovaries

th until t .■ rwaj - :>n of

the s1 . Kt this are not ic-

thei tens.

The young eggs, as fir i
have large nuc] L wi Li, but in t]

- - vesicle is not i t , The

.s, still

•sists
s Lai vesicle can

not be seen. The sections I h-v i

are so un:

before sections
inves . . r observe ius

, '37, "40), Vogt i

vai icroscope, missed

Li v structu . . observers, Brook, Icl

('02) hi; sections but

now, since it is

deve^_ s organ lat

now o

This hag . been described in the fi of

r, but it may be well to emphasize
process is such as vent abso] it act of the

.

III.

floridae. as befoi
possesses shell Pais

.
e-r ■ ;d in its Lese

surrounded ii a thin ellicle :

color

I

I have never be< - •

. . - e to say, the egg of a

; the first, fish
possibly the first vertebrate ich this opening was

discovered. Whether this e -■ is transparent or not I can
not say, but in it Doye're ''43) foui i just over
Lisqui 1 if en "a its diameter as L/llc

A. L Fertilizatio .

jrs vary - r conclusions, or
.aore correctly their conjectures, as tc the time of fertiliz-
ation. A prior - ion to be
effected at the time of transfer. Pre e surest way
to determine the time of impregnation would be to take a male
immediately after the transfer, cut through the pouch just,
back of the forward end behind the genital opening, and then
Lne the eggs in the hinder part of t :h for spermat-
This I had intf . the past
jus transfers fish
kept in a -1, yet I saw the copulation on one
. only (i.i 1903.) between two pairs of fish. The se em-
it solute necessity for keej i se . for the •
es of se. . ::, prevent acrificing either to
determine this point.

I

Huot f'02), Ryder (*&>), - -^s,

it the fertilization t
ulation, while A. f'53) think .hat

it follows lat Ekstroem f ' 31 ) believes it takes place

m belief is t
sperras and ova ar - lultaneoui I have

no direct Evidence, I wish to adduce t. facts cor-

robor • conclusi

I believe th extra

L excitation of t es, descri -ve,

is intended to pr
sexual :':s. In the desci

ttention to .
excitements in Amphibia, Ganoidei a
preparatory t s as well as of eggs.

But thefeecond set of 3na is still more strongly

corroboratory,

during the night I ,ted, i

aquarium for four days, and then the fe ed, her

ovaries excised, cut up, and put into fixing fluids while
some of the ov i fell intc . cavity,

were also :il . When these s xamined s

later, a - ■

closed, other eggs

17

of impregnatic . ' ain two lots c

in l.^"1^ were . the

- to sixteen-celle. . . In one lot, however, th

was fou.n; i lack eyes and

other s in which the blastoderms covered. one-half,

- ourth, of the circumference of the egg. These
Lots of e the si ells, and

the st Ln masses as t

from the pouch. Tims all chance of s havin been

lot of eggs put up i
were found to he in t
them were found two embryos with pector i . ,

It is true that in opposite end! s of

c iffe rent yingi ^differ

hut n in differences of age more than thirty- six hours

against about . s in the a iove cases,

these facts I can ; one conclusion, t the time

of coition both spermatozoa and ova are simultaneously

, and, as the female e her oviduct from

buttonhoi - i irsupiurn, on

L l, into the ovary anci t
fertilize eggs. i; l] occasionally, ut it

a str i .

fertilization.

I

Artificial Fertilization,
- c e
This was tried bj the wet methoi and once

The e sea

in strained sea
lot of r . s careful

drained, and over t s poured sperm from testes which had

been torn up . Ctly dry dish. These were allowed

to stand for a few minutes and were then placed in clean run-
ning sea water. The females were certainly ripu for spawn-
ing, and the males were well grown ^^ had not recently borne
eggs, so they were presumably fertile. A control experiment

of his last lot in running sea
water wit out t ..: ad ition of sperms. In all cases the re-
sults were the same, Vt the end of one aid one-half hours,
protoplas] seen collecting aw

two to t . . noticed t

,-jned sli there was

pretty clearly defined roun

c of orange-red oil drops, ' of four

to six hours, the germinal disc was at its prime, but nei.
then nor subsequent time was there any trace of seg-

mentation. From this time on, the germinal disc gradually
lost its sharp outlines, flatten

I

to pieces. In one lot of e^s at the age of twenty-six hours,

-' inal disc - bad; in another after tw

hours, it was no longer ro re irregular

ry: in a thi rcent

.ive after twenty-three and one-half hou
These e . all alike save that in one lot, so

i taken from the ovary, . \ verj faint ;ion

rotoplasm at h ii tal pole, whil - liter lot

il size. ThisAis, however, "by no
means -.on occurrence. Such differences are met

rope-' serv one-half to

size of lal ones are found. Se

the bias . er, there is nothing un-

usual about the development of s. In t]

iion ' s of the Herri vary

in size in s e fish or in fishes of different localities,

but thinks that this in. no 'fects tl t,

r< Ltj cl
ial fertilization is not possible in th hus con-
fir^... -ori opinion that this would not, take place

in fishes provide ich extraordinary apparatuses for

deposition an - i nation of t s, without their

ever coming in contact with the .Si

live for some

it , It has lone
been salt an*, fish-

es lose their vitality if left in t > time an

not impi s. uatrefages first ascertained this

for the "ike and other fresh water fishes. Hoffmamif '
says thfifct the sperms of Sc .n salt

' 3 ) found Wall-

die after one minute in t]

In this connection the experiments of "uot ( '02) are

very interest} . He toe ngnathus dumerilii

-
from the a of the . . , idAcareful not oo break

eg£ membranes (these eggs were pn fertilizei ),

just before si - - 3), but in no c •••

development £0 on . jut into

Larvae ese too

in forty-eight hours, I can confirm all his results.
I have fou s in segmentation rilJ 0 on dividi

for a short while, but that j all die.

of

discovery of TJruot f * 02 ohn ('04), that the pouch

and its contents act as a physiological placenta, offer the
explanation for the above pheno tena, - ryos,

depending on this for : md food, can not exist out of

the pc

Unable to fertilize artificially the eggs of Sipho stoma
floridae , - It i assible to get from

pouch . show the formation of polar bodies,

I am unfortunately not in position to sa.

process of maturation. For the latest and best this

phenomern iader is refer- .. 3ehren's paper f'3o).

V.

In the Pipefish, fertilization is not necessary to
about the formation of the i i,l disc. Immersion in

.•lies the stimulus as it does in

workers on the Salmonoi , i ''oz), tTisf'93), and

s, so report. hbwalewski ( '86) found it true for the
Ooldfish, as did Agassis a Lan ( '85) for Ctenoiabrus.

.. they state that for pelagic eggs the germ disc is
generally not formed until after impregnation. Brook f ' 86 )
confirms this . Lng, but I have found that the eggs

of the Sar Lsh, Pterophryne hi strip, form the germ disc

shortly after extrusion. Hertwig says (Fandbuch p. 544),
"One can emphatically say for almost all fish eggs that,

%

• transfer i iter, such a powerful force is

concentration of Lsc resulis",

but that "iJ irst, a more - ,

and larger size foi - . j.sc follows".

writers, nor, : k f'66) jr f'87), d -

scribe this foj '.bout by the s of

.There are three :iodes
i n wh i ch thi s p 1 ac e :

I. ^y streams rr>j.. the circu iference only. This is the

specially i" js>. v. -ic

;. , Sec ~: re :>k, yd r, Ki .; sli
others .

II. By streams from the circumference with the help of
little "processions" from the interior of to yolk

( Ziegler ' ' ' ". ) for the

III. In - actions fj , e streaming goes to

the germinal disc ( Carassius, Kc '86)). As best

I can determine, the Pipefish comes under class tv. .

to
This mai L] ; referredA in the sec

deal the periblast.

Intimately connect i foregoing is the collect-

.0 oil drops underneath the germ disc. In pelagic

, the oil is in one great globule generally near the

%

center of the yolk, but in the Pipefish many small orange-red
globules are imbedded in the periphery of the yolk. When
the protoplasm moves up to the animal pole, the oil globules
go also and are collected under the germ disc to form the
"disque huileux" of Lereboullet, This is a phenomenon very
eleosts. It has oeen reported by all workers
on the Salmonoids, by '37) for the Stickleback,
Kowalewski f '86) for Carassius. and by ... 's, ithk
( '37) first described these processes i i « -
Black Sea, T:c says t disc is formed after

the eggs come into water, and that the yell* fett "drops
which surround the yolk flow up to )ut under the

disc in a layer covering about one-third of its upper sur-
face. Kupffer f'68), describing the e; Sumw^Hw!
says, "This fat fo. lss of drops of different sizes
: encloses the germ disc underneath and laterally ','
The two phenomena descri ove are intimately connect-
i . fact bring about another known as the "clear-
t " . Ai the •
center and the oil .es frc i =ry, the Pipefish
egg becomes "clear", _i, _e%, the yolk, freed fro. sub-
stances becomes homogeneous anslucent. At this st
the egg of Siphosto. ia. Fig, i, PI, I, consists of a button-

%

;d protoplasmic disc resting on an oral - c of

oil globules embedded in yolk and covering about one-foui

of the egg, the other three- fourths consisting of clear mi

yolk. This"clearj d< scribed, essentialy as

above, by Pusari f'90), Kowalewski f'86), i
for

[ '85) , ACf isticeps, Cor as ^. ius, and Ctenc ct^

ively ,

In connection wit processes, 3rs,

e sp e
amoebc lents of t cent

he blastomeres u?
to the sixteen-celled stage. Ransom ('66) has also

. - i amoeboid movements in the yolk of eus.

;o assist in freei i . yolk of proto-
Lk, The opacity of the
Lch previ i 'str

operated here against the detection of such movements. Once
or t . - , , ;ht that I did make them out, a

in one hai , I found . protuberance as is figur-

ed by Henneguy ('86) in Trout ge - ■■■- .

i Pipefish egg are i pous

enow e it float, but fr ir location they main-

\n upright position. If t Dver-

turn buoyancy causes :

.0 "breatl . iber" of F. -arise , Long

this rotation persists I can not say, but certainly until
after the closure o . - . Rathke ( '37) first

this in the eggs of E
as best I can make it out, - aterial co-

lter or in air, which fills the "?wisehenraum" re fen

- Pilling this space

in _3_» floridai . it es not coagulate in water, air, or in
any of the fixing fluids I have used. It might be well to
here that this rotation of - is not a new phen -

enon, j Ziegler !' '

vrliest preservations of eggs
disc were made foufr to five hours after t . had been

place.,, i , . tole to descrj ,; act-

ions its formation. In any cat:, however, I could not hope

a classic paper of Agassiz
on Ctenolabrus, or to the more recent memoir of Behrens on
the Brook Trout, Since, I preserved eggs at int< rvals of
from five to twenty- five hours, I have sections which show
the progressive degeneration of the blastodisc. So far as
I know, this Has never been shoi tence it may ue of

1

interest to iv , fe / fi ;ures illus

Fig. l , Pi. I, represents the sharply off bias to-
clisc resting on th , It shows

ters of blastodisc, "disque huileux". yolk sphere, and
egg membrane. Fig, 28, ?i, II, is from a central section of
a germ disc five hours old. The concentration of pro to
is not, yet perfect. As best I ca out all has not

yet emerged from the central yolk, line marks

off a region where pr ; _ _ so closely inter-

mingled as to be indistinguisha . , ;r f '72, . .
17 ) fj .e scribes - out ,

L.I I, shows a degenerating blastodisc ten hours
and t. . structures ar |.uent

in unfertilis: . in the foutr- to six-

teen-celled stages, in ages from feight to twelv
They ■ - - . i about ten

hours, and I am incline I to think, are of fairly rt;
occurrence in degenerating blastodiscs of unfertilised t . .

Strieker in 1865) aescribed what he called an entir
new mode of cell formation in the blastoderm of the Brook
Trout, i_. _e,, a budding off of cel^s, which he thou

. activities of the protoplasm,
figures show bias. one to tw " uds"

u

i or v ; L ■•\.-\c swellings on the outer surface, ana his

one section is very inconclusive. Unfortunately, I have no

the esc of
surface views ofAany of these structures. The folio

year, Ransom reported i si i I formation in the unimpreg-

s of the Pike. These "showed a lobulation of the
concentrated formative yelk, a sort of irregular asymmetrical
rage". After twenty-five hours, "portions of the discus

proligertyas were pinched off and appeared as projecting buds",

TTis reported in 1899 that unfertilized Salmon and Trout .
after lying in water four weeks for i >ck6 on the sur-

face of t iiec by the outpushing of fluid drops

under the surface i r . "either he nor a

figures, ig, , irious observations

As to the further fate of the blastodisc - 'eg-

nated egg of - fish, I can only say that it flattens

out and finally disappears. - . , PI. II, is a central

ion through a blastodisc twenty-six and one-half hours
old, which shows this flatten!: . ""igurepl on the s .
plate shows a blastodisc taken from a lot of eggs in the in-
vagination stage (40-48 hours). It is much lar its
lower surface is comparatively free from yolk. The cont
is evidently due to the fact that on is been lying free
in the sea water, while the other has been under more favor-

1

able conditions ± J , e of

interest to note that il i regnated eggs are often met

with in the pouch with embryos of all stages, none of t
ever "go bad". Ransom f '66) reports . un-

fertilized Trout eggs alive in runni r forty-'.

s. "lore recently, "is f'99) gives four weeks for t
maxi . and - - .. i,sm in the unfer^

tilize s . f the Tr: I

!

yolk spheres. The d€ ii Lastodiscs or

in some cases show these inclusions, but in general are

free fro. . t

.

de script i
. intation of the egg of ^ iphostu.ua floridae , I wish to say
that this is ext.- . , These irregular-

ities begin as early as the two- celled stage and become very
marked when eight cells are formed. The egg under consider-
ation equals and perhaps exceeds that of the Salmon family
in abnor i f cell division. The surface views were

nearly all drawn from the hardened germs in 80; alcohol or
xylol, the opa king i Lbl in situ

73
"blastoderms beyond the eight-celled . . The <

were all made with a Bausc " icroscope

lucida, with the tube drawn out to 160 millimeters. The

surface views were all made with the one inch eye piece and
the two-thirds objective, tions were dr

two inch eyepiece and the one-sixth object i

One-Celled St:
is shown in Fig, 1 , . . fro i abov , 'ig,3^

. II, in section. It is high-archei falls steeply

into the outer periblast (o_.j>.) from which it is civ.
marked off by the circumferential furrow of
This furrow is sometimes so pronoun

of ti Sa lily, t:-iat7>veA .. - its baso.

See Fis f'98, fig, l) for the Trout and (fig. 2) for
Salmon. Kupffer ('68) however, says that in Syngn at hus
(species not given) the ger::i disc is not sharply marked off
from the periblast, and that this condition holds till t
end of the four-celled stage. Most workers on the Salmon-
oids, --ens f'98) and notably T"is ( ' • 3 ) , represent

the unsegmented blastodisc as somewhat sunken in a saucer-
shaped depression. In the Pipefish, however, the blastodisc
oil globules rests on a slightly flatt

3^

area at the up-;1 ' . elow, it is not si irked

off :' ■ yolk, but across its base exte , i,bout

ie periblast t , c -

.asm, section shows several vacuoles

rig] were probabl; il ith oil,

Brook ( 'bo) describes in the "erring a blastodisc with yolky
TJis C '99 ) the U.^ in th
This blastodisc was found in a batch of eggs in the
eight- to sixteen-cel (8-12 hours).

the geria disc i . is formed in from one to four

Hertwig ('03 ) says formation of the germinal

disc in the "Terring takes place in two hours . . the

Trout from seven to eight hours, Fvidentx. - ae varies

with the kind of fish, the : ure, and the purity of

the water. In the Pipefish I have found it to take place
in fro.u four to six hours. It is noteworthy that in none
of the blastodiscs which were sectioned, have I ever fou
a nucleus, id no nuclei ii

. after th< 'ance of - furrow,

Two-Celled St

As in Teleosts generally, the blastodisc e]
slightly before the appearance of the first furrow, and, as

3.
a result, one axis is somewhat longer than the other,
is shown in Pi . , L, I., the normal two-celled stage, in
which - res are equal. In - . , ow v .■, we

have an irregular segmentation, with one cell much Larger
than the other an - vacuole in the line of division. Of

this £ype juite a number were foun .

.33, PI, II,, shows a flat two-celled blastoderm not
definitel. riblast,

nuclei : ■ T :• - farrow has

formed, but the cell wall has not yet come into existence.

.e line of division, the protoplasmic reticulum has form-
very delicate network of dendritic fibrils arra
transversely to the plane of cleavage, Oellacher ( '72,

-scribes - l ures a section thrc cells of

a four-celle - Irout very line this,

says an indistinct streak made up of faint granulations runs
vertically from the external groove -towards the base, Henne-
guy ('86, Lg, 60) giv two-celled stage very

line Fig. 3:; PI, I,, and says that the fine line di1 i i

two cells is bordered on each si clear protoplasm

which is traversed by very fine lines parallel to each other

erpendicular to the median line and that these fine
lines lose themselves in the surrounding protoplasm. His

3C
f ' 98, Figs. 7,3} illustrates and describes similar structures

in the syncytii in early s s.

:
the perfectly distinct cell v/all is inte

its cent , i: a derivative of F

e preceding is of

,35, is a seefcion thr / , PI. I,, in

plane '.-- Lis di-

into a large vesicle at . Verj frequently

livision between the two cells takes the form of a de
cleft with nearly vertical walls, a the

cleft may or maj not dilate to form a small vesicle. These
structures , are often times much

larger thi I see the split

■■j the bre> L s of a series

of vesicles place;, vertically over one another in the center
of the blastoderm. This formation of vesicles in the Li
of cleavage was, so far as I know, first figured and describ-
ed for the Trout by Oellacher in 1872. Balfour { '78, PI. I,,

. 6, 6a, and 6b.) and at so scribes

vacuoles in the early furrows of J: . :e describes

a beaded structure

y are more com . . supposed, that y a

1

considerable part in the segmentation, ^describes

in the "err i ' but gives no figures,

ski ( '55, Pi. XVJ L, Fig. I.) find! - -

the fur re _ ,rly stages of the Goldfish. Agassiz

figure, i Lews of blastoderms of

Ctenol atoms, rows of small vacuole; I whole

lengt] Leava - four eel

stages, but do no - i ;o them in their text. Pusari

Figs. 4 : L, III.) figures in too

sections blastoderms with vacuoles. Some of the latter
vacuoles with large dilatations at om like those in

.35, and36, Pi, II. In t] i] fish, first furr

does not cut through to the yolk. S s. 34, 35, 36, 37,) ,

is respect it ogre risti ri, '90), the

Herring ( Brook '86), Carassius (Kowalewski '86), the Bass
(Wilson '91), the Salmon and Trout (His '98), but^unlike
Merlueius (Kingsle; Zonn. '82), Oadus ( Cunni l - ) ,

and others, which do cut all t

-- ' she 'i. in Coeriola . first furrow

or may not penetrate to t] , There is never any such

under furrow as the Bass and Ctenolabrus s3 ie first

division.

The eggs a at night, as earli as ten o'cl

3
probal ■•;./ hour thereafter,

o'cloc - : are to "be found in stages of

to sixteen LIS. four to six

since
elapse before t ;in to segment, A it takes this long for

gBBm disc to form on eggs in is

id one- fourth hours for the Herring (Prook '

twelve to thirteen in in '

■ ■-.r- Celled Stage.
. t, PI, I. is : tormal four-c Lasto-

derm. The second furrow is horizc crosses the first

approximately at right angles. Thus there is formed a four-
celled symmetrical blastoderm. Sections of this would in
no wise differ from those foi , o-celled stages, save in the
plane a--b where the beginnings of the segmentation cavity
and the periblast would be found. Such a section is not at

hand unfortunately .

. . , Pi, I., a more common fori.,, shows slight in-
equalities in the size of its blastomeres. Such in
ities become more pronounced until they result in renifoj
blastodei- ,6 , PI. I. 'i .- , PI. II. is a nea

horizontal section thro . : of such^for... as Fi| .4 ,

PI, I, i ?a .o of the cells is an arte-

fact. ,1 interest are trie segmentation cavity i

3
the center and the remnants of protoplasmic which

connected the blastomeres.

Int. . - "ipefish c ij ,

many very great and s. irreconcilable irr i ,ies

itly confuse the investigator. These ..
first note: on livi i ur and eight cells below,
two, three, and fo . . .

ities, "lurface views of •
eight to sixteen-celled blastoderms were draw . 5n a com-
parison of these drawings jy were found to con-
form to four gener il types, hi£ as
ination of all i of this stage which had been preserv-

At the close of this section, there is appended a t
showing the relative numbers of these various types.

In Fig, , PI, I,, is shown the r f eight-

celled Teleost blast oc" It is formed by two furrows
nearly parallel to the first and perpendicular to the second
of segmentation dividing such a form as Fig ,4 , PI, I,
into eight blastoderms . In this blastoder ., in nearly
all others of this and the next stage, a considerable elongation
is notice

9, PI, I,, shov; variations of this normal t
ore more c : in the type itself, but are easily

referable to it. . PI. II. shows a section of Fig.

__z^Z-±* In it one of the two central

cells is completely cut out of the protoplasm, while, at the
nner

Aencl of the cell wall, parti} cutting : - ;, there

is a little split which in sections nea .vill

push a short distance to the left but c ight will ex-

tend clear across, completely cutting out and extending the

cavity (s.c). The layer of pro:
the yolk marke . . is ie central periblast and the cavity

it is the segmentation cavity. This, however, is
not the firs': either since a section in t

plane a--b in Fig, 4, Pi, I., ow both, I regret

that I have not been able to find such a section. The outer
periblast f o.n . ) never shows the periblastic ridge figured
by Wilson ('91) for Sfcrranus. Fig.^"1, PI. III., is through

the plane a--b of Fig, 16, Pi, III,, a normal sixteen-ce]
stage, but it will show the state of things in the plane c--d
through Fig. 7, PI, II. In this part of the normal blasto-

of this stage, the central cells ai
periblast ( c,p, ) by a lar ntation cavity, which ex-

tends for a short distance under t 1 cells , in

3
this case cells of Fig. 7, Pi,

, II ., is a section at - gles to

long axis of a blastoderm similar to Fig. 7, PI, I. TJere
the two cel^s are sej -

mentation cavity ( s.c . ) roofed over* by a proto

' ., . . connecting the two blastomeres, A thin split
extends for some distance under eac

arates it from the central periblast f c.p. ) which is heavily
laden with yolk in its rts. Such proto >ridg-

es as the one si t 3 are not uncommon in this and the

next st l . All that can be said of their origin is that

cells were cut out of theA
Structure. to this would be found bj sections

at right angles to Pigs, 3 and ■ , L,I, So far as I know,
these protopl not bee.

ed before ,

- last never co the yolk,

but is so obscu of this latter, that it

has in -ill cases been drawn se - Lcelly, the gener-

al course of the break only being folio.

. PI. I. shows a type oi
far more common in the Pipefish than i . In this

the plane of the third furrow shifts until it becomes e.

33
tori --.I and cuts off four s

four underlying larger ones. ' f Lg. fig-

ures a "blastoderm for the Trout which is almost
counterpart of this. K sectic - ;oderm in

:■■- -. -' veals the structur L.II,

"ere the two central cells stand above sal ones,

ane of d Lally sharp,

segmentation cavity fs.c.) central „ .

are bo reduced.

Another very common form of eight-celled blastoder

.... - six cells below a

a
two above. This is evi t srivative of a six-celled

stage frequently Lth, i - blastomeres

of Fig. 4 f Pi. I, divide by vertical furrows, the other two

cell: Later, however, a division of

these in a horizontal plane would give the structure sho

ig. 11. - ii ire frequently due to

the shifting of this pair of upper cells. gence

is shown in Fig. 12, ?i. I., where these two cells reduced in

size d,ed to one end of the longer axis of the "uiasto-

placed parallel to the

axis but over one of the cent- . .

be shifted to lie at right angles to the long axis

3 5
over one^the furrows separating two lateral cells so that one
cell is at the edge of the blastoderm. In order not to
multiply figures there is given only one drawing 3f
sections from such blastoderms. Fig. L, III. is a sect-
ion through such a structure as Fig. 12, PI, I. in the plane
a- - , . "ere one central cell is very much higher than
of the other cells. 'Hie other central cell is comj
cut out of the protoplasm and is roofed over by tc

from the high cell to the left outer cell.
Following the sections to one side of this, the bri

cell under it are foun - . thu

to have been spli mass of prot

Another eight-celled blastoderm, jui , is :
either of the foregoing, is represented in Fig. 13, PI. I.
"ere one cell has, y orial furrow, become cut out
to lie si- St. Its origin from the lower

left cell is very ivident , side of the structure

is normal save that tb - cell is slightly flattened
its inner edge by contact with this central cell. As _
preceding case, so her be variations in the posit-

ion of this high level cell. It 3 center, at

sdge, or at any intermediate position on the blastod
a section through the plane a--b of Fig, 13, would give a

to

structure etssentin.il/ like in Fig. 43, U III.,

omittin rotoplae i , in f '72, Pigs 5 and 6,

,rE essenti ■ ructures in t]

of :he Trout Joes Henneguy f '88) in his - .38,

. XVII.

- . 1^ ?1. I . , i. un-

atorial furrow has cut off three upper from

four lower celxs . of / vi

fro
is blastoderm is shown in the next figure (Fig.15), Here

the two meridi is

no trace oj or equate row. The segmentation

cavity f s.c. ) is so small as to he almost n<

Ly no section of - . ven but a

parison between it and . . Ill, will make clear its
internal make-up.

These nine figures of - it- celled :
intrc show; (1), t ies which en-

(2), that these ail result fro it ion of '
furrow, which, ordinarily, meridion illel to the

first an< icular to the secon ivision, here

become ec/ , that the irregularities thus re-

sulting .;.q„,' be re to

to the very close of

is 3J i - -
tive numbers c ifferent kinds of - to-

mere s whi eon count

se eight- our

rsist to the close of segment-
- s . • , 8 ,
structure: ; fror . cell in

center), there corr.es - blastoderm,

fro,.. L2 — ri i —

i -
. e structua - the

-

L. I .

"ill

Lot

. VIII.

XIII.

XIV.

2

2

a in

4

4

Pen.

3

3

i

1

ilin

4

7

3

-
i

-

^

3

0 1

i

-

2

-

2

1

o

2

0

'

«

Sixteen-Celled Stage.

Intermediate between the eight and sixteen-colled stages^
are found many blastod^ twelve, fourteen, ana fifteen

cells. These are in fact more a
with exactly sixteen cells.

i s.- ,• ■ , .1. show re idst j ular sixtean-

celled stages that have been fc

the corn: - 3s shown for

0..,rranu>s ' '91 usari f '3 .

These blastoderms av i by each of the c&lLs in

^igs. , , or , Pi, I. dividing into two. In Fig. I6 all
.li save on L, or at

In Fig .17
the bl £ are arrg , ,42, PI,

II., is a section in - i ""i . .

PI, I.j ring to divide into thirty-two cells .

central cells ffi] 1 ividi form ■ -

ior ceils, - he outer cells

cells bot , sit:

of the centrosomes-, L.. ee'lls forj ireh roo'fija

over a con. n cavit; ,

Leir outer ends into vesicl
are covered by thin pre _c sheets or . . i .44,

PI, III. is a section of so., sue'., structure a,s Lg,l7,
in the plane a- - '..< . So - as of this st "been

found in which the four or five cells w cut off fj

,i. i Last, >u . are too infre _ too

L here, Fusari ( '90)

sectio . .- Ls for Cristiceps. a Gc

In Fig. 45, PI. III., there is shown a section of a flat-
-cel La fhich

persists till the preparati - Lnat: Ins.

o f su ch a e v'i ,

I can not say; probably it would in no r from

PI. I . The ej . .-■- ,i.i. • 5,

III. is the circular groovi ,uter

periblast ( o .p. ) in the latter. Possibly -hose figures
derivatives of the one- . stages shown - i . 3^,

PI. 1. In ti. question,

ation cavity fs.c), and a yolk-la periblast ( c .p % ) .

■ outer periblast I . torn

Note the large dilatation of the

right furrow and the protoplasmic bridge cov
PI, I,, is a derivative of some sue:- for >, 11,15,

and 14 of t Late. It is arched but the crest

arch is not in the center but to one si ;he cells lie

¥ t

in tv/o if '

i . Lane a — j , is shown in Fi . .. III,^

clear its sloping outline, and ii-s tv/o excentrical-

ly placer] high celLs, It has L Lerior eel

Lext section is clear of the cej a .ast f c . .

and has proba divisi

outer cell.

. 19, PI. I . , sh
SIX Lis - $ev«*\

- . . II. is a

slo^c: L ^cts over the

struct"
p.p. . t

-vis-
ion walls.

The -a o? sixte - . d blastoderm is

shown in Pi; . 2$, Pi, I. L: a descendant of

a blastoderm like Fig. 14 on the same plate. 'To
description of it is needed, beyond calling attention to the
fact that the five upper cells are cut out by an equatorial
furrow. This is seen by referring to Fig. 21, which is a
ventral view of t;i ... Las ... ' ere only five of trie

The

not reached the base. The s
avity ' s . c . ) recalls that of Fig. 15. Let

. ire the next, Mo. 22 , which is a view
similaj - -celled stage,

.sax cells rusting on the yolk, six in

of
the whole enclosing a spacious itation cavity,

.ion cavity fs.c.J ex"
. i g. . ... be given as

a section - . ssin

keystone cell. The centra .as not yet cc cut

itself off from its m - cell to

a resting nucleus curiousl;
There h« , !

: , such sixteen- eel
considered typical for i efish. Of these two are suf-

ficient h ii... the usunx t s to be called noi

but a great majority, fully ninety . - iose stu< L

are like figures 18,13, and 20, PI, I, In this connect-
tion, Hertwig's stat .-. , pp. -S) wi reference

to the fourth segmentation : sixti -cell-

ed sta , i interest. says, "The end result is every-

where the same, a 'checkerboard- ' arrangement of sixteen

blastomeres, four i

inal ceils". ~Tov; untrue this is fo .Mice

i ile shown

x e ..

ntation.
ttors ar< .. . .. ology be.

the first and second fur-rc i t '"" a. Dhibian eggs,

but whether o£ not the third furrows correspond is a ver;
bated question*

-Tof fmarmf '61) fi scribed in pelagic fishes

the first s ition as < ., dividi from

periblast; but, later f his error am

clared that in SaL:ii- i furrow is equator!

i rd furrow in rout

is equatorial and divides or from eight lower cells,

the latter not being as yet off from a periblast,

Rauber f *83 ) made a careful study of the subject bas
rn fact, th Lbian furrow in

c as e s is not t ru I . bu t avo i .

forms many structures L . , PI, I, He con-

cludes that the first equatorial furrow of the frog has been
lost in the Tele, aorizes t teleostean

Le- avoidi . - - .) ' the

frog. Forthis interpretation of Rauber se< il£ [*&!,
214- 1§) .

' '85) thii Lbian

equatorial farrov/ has become vertical in the Teleost, and
that the horizontal division of the four central cells of the
sixte i- e into four o . four inner lying

cells is the first equator- ,

latter statement Kopsch f'Ol), fro Lone, is

in full accord. Brook f'86) describes, from sections of
Herri. . . . 1 ) , an equatori

separ .e four blastomeres from b e pei . . List

y Pi. XXXI. - ■ . 5) finds the second furrow in

Crenilabrus to be equatorial, and says that PCupffer f
the same in th 'ring. In Cristiceps, Fusari ( '30, Figs.

4 and ^, Ls.I. a . at in the sixteen-celled

, all the cells ire united at t next

sets
divisionA sixteen central cells free from the yolk ana fro;::

sixte. L ceiis. This he calls the equatorial

division, Wilson ('91, p. 215) Ctv all

W»\ts. ), in th ,ation of Ralmonoids,

orial division follows t] . ei

celled stage, alt] it someti o s lier.

An equatorial segmentation has been pointed out in cert-
ain eight-celled blastoderms oj . toma,, and this gives

ry decided resemblance to the upper surface of di-
viding amphibian eggs. Gronro [ *90 ) (Red r"
buch) gives a series of figures for s of Tritons, to
which, the figures above noted, show very striki c
es. The Tritons with its
o f j o L ,

ic condition. The text-fi produces some of the more

striking foems to which reference will 1 . The r -

ulance is so striking that no e; .son is calie<

for. - -■ ig» I., compar " - . - , PI. I.

also Kenneguy's f *t . Lmost i

For a figure i - ... II .

, 13 -c . . * . t inclui

Lates, is on .

i . 3 . . a,ri-

ijni this is sufficient to
S similarity i forms.

we have here ion is be; stion,

mtation - - ' . ,stoderms in

questic ,is 'i ..or at least s very c

thereto, and it seemi too far .at such

Pipefish blastoder Figs, , PI. I., thei

a reversion to a type of segmentation esse;;
ia.

Thirty-two-celle

of this sta - ig. 23, PI. I , ,

were founc thirty percent of one lot o:

sparingly in all ot] ig. 3 is plain

ivative of forms Like Figs, it

normal, is noticeably differe: L r "ilson's
figures o for Serranus (Figs. 6,8, 9, a

;To section of this stag r± - . Its internal stru-

cture wil] j reference t . • -', PI. II., a

sixteen- celled blastoi divide into

,wo central cells will divide horizontally, the two 1
al ones by an oblx - suiting in six surface and two

interior cells. ( ilson's Fig,

- . - . '1. III. is a section

. d ignificati

others. It serves to show the inequalities in the

- f the blastoderms. The
flattened above, though retain- rounded

right the section cuts the point of a sixth c<

0 I

segmentation cavity f s.6. ) is partially fil celis.

tell
The 1 - ' to have been cut off from the cen-

tral periblast f c ,p, ). from which it is y a cell

so delicate t oil immersion only .'/ill detect it.

It is lik - Last further in that its pe con-

tains . ranules;

i. I., is an arched type, writ L hest

point rather nearer the Lower side. The twenty-seven outer
cells are in three tiers, a

sharply marked off fro Lrs 3 is but little differ-

ence in level between - ihird tier. There is

noticeabl

1 — 1 - i,1ail$j .- : first, 2 — 2

the second line of division referable to Fig, 4 .

A central section throu - . in the plane a — b is

shown in fi- ,5Qfl. Ill, The peripheral cells form an arch
est point slightly side, and enclose a

segmentation cavity which is almost filled with cells. The
two smaller cells 1 ve been cut off from the peripheral ones,
the larger probably from one ofits fellows. The periblast
( c ,p . ) is thick and yolhy. A more pronounced large-en.
type is Pig, 51, "ere the segmentation cavity is somewhat

eccentric, and , as in the preceding, the ... over-

n

s the base. The spacic 3ntg/tion cavity f s.c.)

contains i - -its on a curious tongue of protoe

-ion on the left..

PI, I,, is a 1

whose L 3. Its highest ceil

of t]
x is slightly eccentrically placed, and one of > sAis

_ , III,, is a c en-
tral section through a similar s itly older blasto

targinal cells are sharply marked off frc 'iter

Last f_o,j2..). The arc is high and round. On the left
three cells ar< from one of t]

a tongue of protoplasm, fr a cell has been cut off,

projects int I Voion cavitj . T

torn off at t] si Lter redui

of protop . ol.v adherent below, thus

it the br

i . i3 s •■ -■ sture by no means uncommon in t

; ^iphostoma. It is a thirty- two- celled stage in
riblast has yet been formed. The cells .are in two lay-
ers ; che long ceil on t 1 right is nea to di-
vide, rnftath the whole is a thick layer of protop
in which three vertical cell walls extend downward and are
lost. Later transverse •vails wi or and cut these

i

cells out, of the syncytium, finally leaving

- ion cavity (jj.6. . )
i . vacuole (v. . ^.er

( '82, Fig. 2) Lmost identical su'uc^

Kowalewski f '56, ?igs.

- ions in t . . fish. • .

9 especi ..cri"bes a si^iL'u1 structure in the

10)
confirms the figur 'kers

on the

?1 . I . , is x v --v inter* s

[vision am foufc-

teen in the ot: •. 3i rith

occasionally in st i of from sixteen to sixty- four cells,

hut especially abound in the eggs from one fish. Out of

twenty of in picro-acetic, five were lj

;he one figured, artefacts is shown by

same Lot killed in formalin also
of v,.
cunt \inec. divided blastodej ..-. , unfortunately

loted . In each division

and the line of separation is broa

Last, The; i >ut very i j in

Fi ,54, PI, III., a section xasto-

ft

derm. In the .ore is a small se wity

f_s_j_c,), on the ri

- There is no

Cells have t out of m,

:h are foui cal cell

umber of vacuoles (v.), an . be-

low wi yolk. - . . .

sixty- four- ce . AtA

blaatoderms it

is here In - A

L out to a vesicle

line is i '/o-celled stages a ove .

i cavity i >ortion, Lug there is no distinct

periblast, of proto] . .

large vacuole ' Ik in i part. In s

c as e s

] oints tow

if a fine thread, used to separate the parts. had elon

v .

i <s conditions as s.
found
Is in a short section on Corijegonus in

Eycleshymer ' s paper on Amblysto others).

This . , however, that these divided blast

do not result in double embryos* ".'. told

the

tru e f orA Pip e f i she s of Be au for t , fo r al the . s o f

larvae ai ■ . .ive or preserve! ,

been ex^-i;:e;.., o

-
fishes contain: - ■ •

( '62) descrih •

anals.
: ,, n^nathidae of
of the snout, eyei md tail, :s to retai

of (

Fig. PI. I . ■ - -

in three tier:

ation in one derivation of the com •-,

found in the eight-cell curiously -

taent of c i cells.

, it becomes more so later;

finall: is lost, toderms

he come almost circular in outli surface views of lat-

er si ven, since, as the cells grow smaller,

ilaj io ■ ij : i more an .ore the ordinary teleostean
form.

6^

. ./-four Galls.
Artifici . f Llization bein
one cs Lat into

greatly vafj ing shapes of the bl ust

r of rows of ceils in
. . rriters do, so it has

is to cou L] her-

al cells i - ,1 section of . then, a;

i

c of surface cells
is found. The sise of the cells serves us a check to this.
L. IV,, wj .Is, is fr

1 type ofA sixty- four- celle stage.
' ■■ . . ) is thj s a cell not yet

cut Off fl . ' ■ . : . ) i s fil]

cells, some of Lvide .

derived precedi

- , . ..a flat blast e „ and, .,

bj c- . 1 . II,, is seen to b

undergone considex^uule division, in horizon.

; .... segmi n ivity,

are
The large nuclei,, in t. . ., ■ d - Largin-

al cell there are two large vacuoles.

The high-arched type of this stage is shown in Fi ;. 58 ,

55
•ivative of a structur Li . .Ill,

falls steeply into :he outer periblast f o.p. ) . the cells
ore all r uclei. are

i
periblast f c.p.) . Sea

of the cells. The mitotic figures indicate that division
into the next .

In Pi . 59, "
section is si-
one cell

i

In the central section t] :ion cav-

il. ( s.c . ) bee 'ger. The outer ceils are

flattened on ior, le structure is v

- . 55,

Stage of One-hundred- twenty- eight Surface Cells,
The normal gently arched type is represented in Fig.
a nearly central section of a blastoderm of this stage. The
central periblast ( c ,p . ) is here thick and fairly -.'ell de-
limited from the yolk below. Of especial interest 'are the
cells in ' cut out of it into the segmentation

cavity, 'reny notable is I cy of vacuoles (v.) in this

■

process. The cell next to

part a nucleus, the first
- -m,

,61 _Xi - -

central peripheral cells, like tps«

i i
blast . i: Lne, a

is thicke • an ' so that onu can find no line

of sep LOle has c

■ar - . .

- . oints of intex section:

the presence of vacuole! - Lp to se] irate the r:

'

ar s ,
having some yolk particles in it; a irs of nei

ing cells with spindles at rj

last illustrate the exc irregul .cation in the

Pipefii

.63 is a near 1: I section t

. ite "between t} the thick- .It,

sharply marked off from the outer periblast which it over-
-- ht. The . btion cavity is reducec

5
interstices between the c^ns, ah alon
in ali the sections ceils are being cut out

An especially interesting case of this
is found in the v - . . . cells show mitotic fig-

ures, and in o si .e nuclei small solidly

staining round - "'net ion.

derived . i . is a fine . of its

-at ion cavity is v
ectly fr and

Low U of cells cut out of

it and at the left a nucleus under I inal ceil and

clearly derived frcmit, ' .• the center, the

periblast is re Lne. This ich

f '98, . rout.

- I hired- fifty- six Surface Culls.
The normal type blastoderm of this s i

• >,b« e cells iyin upper suj consider'

k /or parts nearer t. e peri-
To right and left are furrows -'.
ing to cut cells out o
cells nearly free from it .

s

- . 'uive of Fig. -63, in its general

outline an L ite its o

o.P. ] fr< ... cells. sriblast

is somewhat sunken in free frc

blastod< ra. Lty is, ecause of

t] is

•e ssion .la is only i .is,

irface to be .

as t ig, Gl..

The t ... i . 67 from a nearly central

-on. Th rence in the size

of the blastomeres, sc - L ls large

as ot] . TTere again are ceils being cut out of the basal

periblast. T\ - s fro..; rou Ls to

Letely cut out ceils.. i i nuclei

se. At ro c^lls "

stout protoplasmic uri

. 2 o, Pi, , , i s a

spacious segmentation cavity is loosex.

ed cells, st is throughout the blasto i -

the form of tw

in the F_ . ion, but in iter it i. md

obscured wit] , Nowhere ia the whole blastoderm are

cells being budded off from it. In t Leral cells,

even in this advanced st proto-

ridges.

rizontal section through su

- . , This is in -o show

the an t of ceils in horizontal plane. There is
here a closer tion of cells to the periphery, the
inner row being a derivative of the outer, while in the cen-
ter the ceils are more scattering.

is -'-■ intermediate between those

from tfhich igs. 57 , PI. IV,, ar JV

sections i , 65, outer

cells ahou .to elon; . .:nr

than the interior . . s are nucleated,

and in one a ceil wall is cutting downward. While trie peri-
blast, Ls resting on it and e-
in the blastoder-i is t evidence
ed off.

-
on t 3ur i . c e .

, is very similar to t
cedin - . the cells are pn in size,

bhose on the surface are noticeably elongated, some be-

:onnections — ;in- '

fcl

.. . nu-
clei are in process of division bj , -<r-
The 01

totally

,72.
flatten*
pointed, ant; one on t is bi'nucl . , ?he L sto-

uniforrn in size, and on t is

mt cell Late nucleus. clei

stain soli L; , B periblast is very . i ile

nts, it I istinct below, 1

are two nuclei in the periblast. One is in
out c /ill probably be formed,

cells

7 is an excellent illustration of
The bias" - Lstribution,

.. noteworthy for t] ier of di-

:lej . spindles at all angles,

terest, however, centers in Lblast,

possesses many yolk granules, but is perfectly distinct.
In it to the right is a nucleus dividing by mitosis with a
spindle consi Lose in the elastomer es.

62

ihe section cuts through a chromatin bus
at rig spi .At the ext] t is

found, for the first time, a nucleus in the outer peri-
blast, -blast in this ci is very rich in
nuclei dividing by mitosis, A curt ination s S
one vertic 6- horizontal ones. Another blasto-
derm, of t . stage, contains , in its j
blast, thirty-three oblique spindles at all angles fi
nearly vertical to nearly horizontal, i
horizontal] - vertical posit i
in all sixty-nine spin I (none twice). There
a a very few solidly staining nuclei, but a aber
are ci.it, as above, t eee
are not c . There can be no doubt I
stand - sitions.

Last ! . 7- . The cells

tot uniform in size, a
LI ones. ^ciei stan: solidly, out s

contain spindles, Two bi-nucleate cells arc present,
one i] ;ing very . This condition

is far from rare in thi: .

cases have been particularly no . The periblast is

thick, yolky, and distinct. It c s sei u-

13
olei, and a cell is either bBing cut out^or is in process
of unitii , In other sections :

conditions are fou . e reentrant angle, between

outer peribla; "Rand in this ->,.-. , recalls the

65 , Pi.
in His' figures for t s referre >ve.

Lis.

,75 represents the normal type and presents .
points of interest. The surface cells • si

Jacent t re other cells with their

is. eight angles

j er in places two cells . i ter cells

tendency . .

The chief interest however centers in the p Lbl . This
is notably free f] < .Wand is drawn exactly as it appears.
Nuclei ai Lj i --ex-

tent in all sect;. , nearly surrou vacuole

of the center. A.t th
recently been cut out of t . is Livi in : Pto-
sis. A large number of cells rest on and indent t]
blast and are either being cut out of or added to this 1
er. The close juxtaposition of these cells to nuclei in

C4

the periblast would seem to lead to the former conclusion.
The second type is represented in Pi .7 , which, ji

-■ oi' cells in the periphery size,

is from a blastoderm slightly you; 1 the pre
The i t is sunken deeply into the yol i,s, thus
nearly doubled the i tion cavi

filled with scattei . . iblast is so

obscur - no nuclei could be found. It is

here free from cells, but Ltion

in this respect like the precee- . r

', is a binucleate cell, its

Fig, 77 is from a roun "' about the .-.

' : spok-

en of here, for the outer ceh;

cavity is small interstices be-

tween the cells. Tl i ri .ast is full

of 1 abounds in nuclei in sections

the center seem! Lis,

left Ran th< re is nt ..itotic f.
as any in the blastomeres,

do better illustration, of the lens-sl - istoderm,
so c. istic of late teleost segmentation, than i .

U -
can be iven,

.sure of the cells

^shell causi - - - blast to be d1 ' . ?hus

the s -on cavity has be -lis

-•re scatti . . receding. The cells

t-.vo's , t r rs ,;. four's.. peri-

. t has several nuclei in t. .tion. There

is a well def 'mic stratum", as 1 .isb

writers t« • layer of cells.

. 79 represents the this, s

need detain us but for a f€ ts. Its outer cells are

and unequal in size, a interior cells are

the largest of all. T3 - last is ver; thick, y<

and i from belov/ by large vacuoles. On the left

. cut out of t]

a cell in 'iblast, while in the center cells

.

This blastoderm is closely related to that illustra

section by "- .

Pi . " is a horizontal sectio. . ich blasto-

vert .
derm as that shown infection - ig.78, -. . It shows

the loose of the interior cells, am - a,wn-

out cells of the Peckschicht . , :en at sev

points, i rocess of section i . .

Lates t,tion.

From this time on, it is not
possible to folloa i . ut son e figures

be introduced to s] Durse o. ment,

. VI., is probably a dec , form

72, PI. IV. Thea dc strat-

um", the cells are loosely sca:ter' nt-

ation cavity. The periblast is quite distinct, free from

. -. ist across the border

from one of t] Lei is a cell, in and :e a cell

lies i ression ii Lblast ,

Fig. is i -•-,-. , cells fairly

closely crowded in 1 cavity , an;

periblast out of . . ar - - - ito which

lose themselves. At one or two places, the peri-
blast is reduced tc ickness of a c

ioring sections nuclei abound in it. In the right
outer periblast tv/o tripolar spindles arc found.. These
have been noticed occasionally in other sections.

,83 is trie typical Teleost late lens- shaped blasto-
It closely resembles Pusori's ( '30) Fig, 9 for

i. •

Cristiceps3 plicate oj i x' s f'96)

. 3 for the . in correspom i i . press-
ion or the blastoi i Lk is pro to
pressure again! . 't of
the l is a ver;
'

I .
a cell

. cut out . The - i-

'A

. i . - - ells, nei" rigi nor

ratory to I ion,

- . the cells are be-

peri L . : , to cro
in th of the bias L sub-

germinal cavity ( £ . - . c . ) between them and the periblast.
The lin x is, i

the .Is, roost so

■ very thin
skin- . 1 ist iS comparatively free

... . im

of semi-diagraramaticall; .

second type is represented in Fig, . he cells

b

:' .. . - 1 c . ) is ver;
i - that

.

type. In -
so closel;
prece. , ■ cavity is fori

distinct

■ e cell is
left is

rhi

-

Two . siz;v of

ceil:

Lat .

ill . . nor-

t for this sta^-e,

close - - '

bv - - ■ -.1. l ca ri . , , . iblas

auclei,

it

■ -
- - -

70

St .

' this la;
j ies of stru een noted in the ;ions

Lates. It is not my intention
extended discussion of its for i . rer it

will he well to describe briefly the various modes of its
for ation in other Teleosts anc to . of these

classes the Piperh; s, and fi

this ertabj
jieosts,
three ty . :

I , ] Ln whi it: 'ough

to the yolk, periblast is forme y a in smic

sheet exten' i i lom the "Ran ', mneguy ( '£ .

63) shows this ver; for the Trout.

II. In eggs in which there is no lay

under the germ-disc, or those in which the protoplasmic i

: . from the yolk, th - .ast is for

when the inner ends of the cells in trie four and eight-celled

i
.. is the mode of ;
"err anus ("rilson *3i), Ctenolabrus ■ ■' '85),

?1

' > 1 ) ,
Ill, ; in whi c

ation c isc a there is a layer

of oil clrc isc, the cent-

very peculiar mc . - i . lIs are cut out of

the protoplasmic disc in successiv ove

Last is mt of

"blastodisc le process has ended.. The e; ^ lig-

ation for this is that the prot Dntinues to fl

out of the yolk into th isc until i has

i stance . f fer ( '68)

untj j,fter
the four-cellc .

ion for escrih-

i most vrorkcrs on onoids, n<

nn( '88) for . Latest oi

Kow
found essenti . ion in .Ca- nd

Eolyac ant s .

The cent nuclei, in types I. and II.,

originate by division of . ate

centraiv/-v . [II, , the

Aants of ition cells,

i th-

72
oris of central periblast 1... in types II.

- " I . above . In Fi ... )

i-e stages, there is ! -

ation for the periblast w] - ivei -a that

fro:, it there could ever come an„ after-segmentatic .

On the oh .... , ,61, the

rotoplasmi prim-

'ter all the blastc

been cut out it,. It i: ill re, La

.ion of nuclei form-

"wreath" by the disappearance of cell walls,

has, because o i,city of i . seen in

t her it ta r not, I can not

The L iher, a

sh, cells are bu central peri

and added to the blastomeres, can not here be taken up.
However this would see. i legitimate consequence of

e of cell formation as that i in type III,

. . i,tion in ... 77 , 7$,

30, in which a perfectly definite yer has

If theg s are co .. His1

12, this clearer.

7

For a At Her discussion of the or. £he peribl

its nuclei, and of the fate of -

Fusari ( ' , .er { '87 ai

.
At this point, th - develop

to rest, . of the

i

hut the difficult!..

; to a clO!
. .
teleoste ...

al origin of its periblast toge f

me - ation" of celli . co m

encet: , figures in this

. . i s and or

more ;s, obtai - Lree fish

. ' ;assiz, A, ...

Fis . .

, , . Development of Osseous

Pishes: II. The Pre-Embr/oni of Development.

,irs of the 'luseu Anatom, , Vol,

'-of
Elasmobra Lshes. on,

pens, Hr. ~i _ Ry.
i.leneies. ' . Hefte, 4bth, II.
. Cerent, . rablastes und der

iblatterdiffer 3 Ische ,

Jenaische Zei - ss. ,

1887, Brook, nation of - i,yers

in Teleostei, Trans. L

I. Session L - ,
ohn, .

.
T. T,
of the Ovarian Ova in Cei Pishes. Quart.

Jour. Mic. Science, Vol. XL,

of Cochi -
Proceedings of the 7ool^- :iew of Lc

. . The Fishes of India, etc. Lone

i,s for . ie : u'iy Devclo
.
. 3 .es Oeufs

media et " ion.

. Extraitj s -

Mittheil aus .J^hr.

1831 . Eckstroei .

iens.
ho ..

': . . it of Ambljrs-

eervations or. Some 3t ,tes.

T our n al of r Io rpho lo gy , Vo 1 .
. ' isari, . 5ul] U di sviluppo dei Teleostei,

Atti . . ' Lince; ies 4, ^ol, 711.

Resume de l'Auteur, Archives iologie,

s , F , i -i t

Felix ,
Oeeeux: E La Truite.

de 1 'Ana i ; la Physiologie.,
, Her . - - , Der

sproaesSj vergl. un . Lel-

1898, . - . -

Studien . . ys.

Class ,

.XXIV,

. . Pro i . i .

. , :to .

1881. "offmann, '". K, Zur o a Knochenfische.

Ve'rhe - I'oninkli jke Akad

. , Ueber den Ursprung urn" die Redeutung i

sogenannten "freien" bei

.... Zeitschrift fur Wissen;
Zoolc ie. . XLVI,

1902, . ranch-

es. Sciences -laturelles, Ser. 8, ..XIV.

1891, r, 0, Tne Spej i . .

; . :> 1 . V .

sley, J, . . .

Bostoi
of Nati is rs, Vol . Ill ,

1872. Klein, I. Researches

ent . scopi-

cal Jour 1, Dl, ''II.

sch, ?r , i - . - .oblasts

unci ' . . Intern

" T- 1 .
ie ersten Fnt1
'.nochenfische , Zeitschrift fur "issensch.
Zoolo ie, . XLIII.
- .

for, . Entwi

Knoc , ' - civ fur Mikr, toiat . i .

1871 . A. Note pc

etc. Actes iete Linni VIII.

1891 .

u?, Tredje Delen. Upsala.
1887, List,, J, '■' . Zui

fische. Zeitschrift fur is . ie. Bd. XLV,

3,894. . L

die Fntstehu ien

Li ere. Knoc . 2 tin Oiociete' .

Lai - .

■ . . s r'-

ostc _ -'., . -- Utvi

, .. Note sur un c

"III.
. Oellach . - aur Ent

te : enfische nacl

enei . Zeitschrift fi Lss.

1634. RacovitBa, Emil . Notes de Biologi —

et Fecondation chez 1 'Octopus vulga . i.rchiv

Logi srimentalej Ser .3, . II .

: \tions on *vuie of Osseo ;

. . , rol. 158.
183". Rathlce, Heinrich. "ur ' Li , \rchiv

fur Anatomic /siologie

1837. UeLer Le Entwi gur

_ : -

1840. Ben Syn aa . 'oreus, e1 .

Archiv fur ^nato ai' Physi i

a . itniss der Zell

^. VIII.
1393. Rej . zoa

of th Lll-Et - . Re] c -■

issioners.
, Retzius, A . 3lar

-
Vet Linger, Stockho] .

1882. Ryder, John *\. A I and

ranchiatei - . hudsoi

ius). Bulletin . . ii mission, Vol. I. for L

, A Sontrihution t . o£

tc, etc. . '^. Pish

:ission,
1887. Or. b] Oeeeous Fishes, in-

cluding T'lar ...

Fish Commission, Part XIII, for li
. . i Einfluss dcs Dotters

auf • Gastr L it ion und

'irtelthiere. III. L )stier, Archiv
fur Entwi eke lung smechai ik i t. . HI.

[ . Strieker, . Lckel—

L . Sitzber. .

i

L V - ..lie
co: be . , etc , .es,

» , Tome XI.
1891. Wilson, "'.-.--\

carius), . . .. sion^

... IX. for 18 .

. , von Salmo

. Di bei

fischembryo. ^rchiv fur Lk. .

, Die Entst ;es bei

- . . , XI I .

- at
ille , N . C, - the

iblic and

.,1883- .

. s -
t .

I "- -

■
ille, .,1893-
Instructor .in As

. ...
Little Rock, '

ent assistant in general
Biolo . subjects are Zoolc

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