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UNITED STATES NATIONAL MUSEUM LA JOLUA, C
Bulletin 100

VOLUME 1, PART 4

CONTRIBUTIONS TO THE BIOLOGY OF THE

PHILIPPINE ARCHIPELAGO AND

ADJACENT REGIONS

REPORT ON THE

CHAETOGNATHA COLLECTED BY THE UNITED
STATES FISHERIES STEAMER "ALBATROSS"
DURING THE PHILIPPINE EXPEDI-
TION, 1907-1910

By ELLIS L. MICHAEL

Of the Scripps Institution for Biological Research, La Jolla, California

WASHINGTON

GOVERNMENT PRINTING OFFICE
1919

SMITHSONIAN INSTITUTION

UNITED STATES NATIONAL MUSEUM
Bulletin 100

VOLUME 1, PART 4

CONTRIBUTIONS TO THE BIOLOGY OF THE

PHILIPPINE ARCHIPELAGO AND

ADJACENT REGIONS

REPORT ON THE

CHAETOGNATHA COLLECTED BY THE UNITED
STATES FISHERIES STEAMER "ALBATROSS"
DURING THE PHILIPPINE EXPEDI-
TION, 1907-1910

By ELLIS L. MICHAEL

Of the Scripps Institution for Biological Research, La JoJla, California

(Oft

WASHINGTON

GOVERNMENT PRINTING OFFICE
1919

/*) y LIBRARY

UNIVERSITY OF CALIFORNIA
6/1 SANTA BARBARA

CC, MS"

REPORT ON THE CHAETOGNATHA COLLECTED BY THE
UNITED STATES FISHERIES STEAMER "ALBATROSS"
DURING THE PHILIPPINE EXPEDITION, 1907-1910.

By ELLIS L. MICHAEL,

Of the Scripps Institution for Biological Research, La Jolla, California.

INTRODUCTION.

This paper is based upon the chaetognatha collected by the United
States Bureau of Fisheries steamer Albatross during the Philippine
expedition of 1907-1910. Chaetognatha were taken at 46 stations
scattered between the parallels of 21° 31' north and 5° 36' south
latitude, and between the meridians of 117° 53' east and 127° 44'
east longitude. The collection is represented by 12 species of Sagitta,
of which one, Sagitta philippini, is apparently new; one of Pterosagitta;
two of Eukrohnia; and one of Rrofinitta. The species of Sagitta, in
order of the number of specimens obtained, are: S. enflata, (2,800);
S. Tiexaptera, (700); 8. ferox, (600); S. pulchra, (550); 8. neglecta,
(425); S. bedoti, (350); S. decipiens, (160); S. serratodentata, (100);
S. planktonis, (85); 8. minima, (2); and one each of S. macrocephala
and 8. philippini. Pterosagitta is represented by 32 specimens of
P. draco; EukroJinia by 6 specimens of E. Jiamata and 5 of E. rich-
ardi; and KroTinitta by 3 specimens of R. subtilis.

Most of the material was preserved in formalin and is in excellent
condition. In some cases, however, alcohol was used. Specimens
preserved with it are distorted and the tannin extracted from the
corks of the containers has turned most of them quite black, ren-
dering identification uncertain and, in some cases, impossible. But,
in so far as the collection permits, tables of diagnostic measurements
are given for each species, enough measurements being made on each
individual to enable reconstruction of its outline. Otherwise, the
species are not further described except for those concerning which
need of description is indicated by the literature. In lieu of descrip-
tions, however, references are given to those published in other
reports, particularly to Ritter-Zahony's (1911) revision of the group,
which, with two or three exceptions, is adopted as my basis of
classification.

In order to make the report as serviceable as possible, keys are
supplied for identifying not only those species obtained during the
Philippine expedition but all the species in the group. Several new
species and five new genera have been described since my last (1911)
report. In addition, Ritter-Zahony (1911) has called attention to
and admirably illustrated specificities in the presence and absence

235

236 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

of rays in the lateral fins. In devising the keys these specificities
are used and, except for Sagitta maxima (Conant), which I still find
impossible to separate from. S. lyra, every species recognized as valid
by Bltter-Zahony (1911) and several others described subsequent to
his report are included. There is great need of keys for identifying
poorly preserved material, but the minute structure of seizing jaws
and other skeletal parts of the head, upon which such identification
depends, is still undescribed in nearly half the species. The keys
included in this report are therefore adapted only to the identification
of well-preserved specimens.

The area covered by the expedition is too large and the hauls
were too scattered to yield definite information concerning the dis-
tribution of the various species obtained. As pointed out elsewhere
(1916, p. XVIII), variability in plankton distribution is enormous,
and hydrobiological relations are too complex to be revealed without
frequently repeated collections in very restricted areas and searching
hydrographic observations corresponding in time and place to each
net haul. Even though thousands of individuals of one species and
none of another be obtained by a single haul, no conclusion is justi-
fied other than that the former species was obtained and that the
latter was not obtained. Such data afford no adequate evidence
for concluding that the former species is more abundant in or more
typical of that particular locality than is the latter. Had 20 or 30
hauls been made at each station with nets of similar filtering capaci-
ties, sufficient evidence for such conclusions might have been obtained.
But rarely more than one haul was made at each station, so the data
3rield little else than records of occurrence. These records are given
for each species.

In comparing the species occurring in the Philippine region with
those obtained from the vicinity of San Diego (the only coastal
region of the Pacific off either of the American continents from which
chaetognaths have been described), two interesting and suggestive
facts come to light: First, those species obtained in largest numbers
from the Philippines are those which, as a rule, occur rarely, if at all,
in the San Diego region, and the opposite. Second, of those species
common to both regions, the number of teeth is greater in Philippine
specimens.

This is contrary to what might have been expected. For, judging
from the fact that chaetognatha collected under the auspices of the
Scripps Institution from as far south as 23° north, off Lower Cali-
fornia, are essentially like those within the San Diego region proper,
and, realizing that this is but two degrees north of the northern
boundary of the Philippine area from which chaetognatha were
obtained, one would naturally infer a close relationship between the
Philippine and San Diego faunas. To find it quite the reverse is
therefore suggestive of a fundamental and far-reaching difference in

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS. 237

the other faunas, and so of the whole economic and fisheries situa-
tions of the coastal waters on opposite sides of the Pacific at corre-
sponding latitudes. Extensive exploration of the Pacific, particu-
larly of the coastal waters of Central and South America, is needed,
however, to discover the full significance of what is here so clearly
indicated, and it is regretted that no chaetognatha are described
from these regions. But, in spite of this, it seems probable, from the
meager data at hand, that conclusions reached through explora-
tions in the western Pacific are largely inapplicable to the waters of
the eastern Pacific, and the opposite. Some space is therefore taken
at the close of the paper in briefly comparing the Philippine and San
Diego chaetognatha. It is hoped this will emphasize the need of
more extensive explorations, and that it may add its mite toward a
better understanding of the fishery problems of the Pacific Ocean.

KEYS FOR THE IDENTIFICATION OF THE CHAETOGNATHA.

Ritter-Zahony (1911) has been the last investigator to thoroughly
revise the chaetognatha. He recognizes six genera — Sagitta, Ptero-
sagitta, Spadella, Eukrohnia, HeterokroTinia, and KroTinitta. Sub-
sequently Germain and Joubin (1912) added two more — Pseudo-
sagitta and EroTinitella. All are probably valid with the possible
exception of Spadella and Pseudosagitta, the status of which is baf-
fling. Most of the differences given by Ritter-Zahony (1911) between
Pterosagitta draco and Spadella cepJialoptera are certainly no greater
than that between those species of Sagitta in which the skeletal part
of the vestibular ridge is present and those in which it is absent, and
this difference is clearly of subgeneric rather than generic value.
On the other hand, Conant's (1895) description of Spadella schizop-
tera, although fragmentary and wholly unsatisfactory, reveals a close
affinity between that species and S. cepJialoptera and at the same
time makes the genus to which it belongs unmistakably distinct
from Pterosagitta. Furthermore I have seen specimens of neither
S. cepJialoptera nor S. schizoptera, and it seems best, therefore, to
tentatively recognize Spadella as valid in spite of the fact that the
characteristics by which its one well known species, S. cepJialoptera,
differs from P. draco seem of subgeneric value.

The validity of Pseudosagitta is ably discussed by Baldasseroni
(1915, p. 101), who holds its single new species P. grimaldi to be
synonymous with Sagitta lyra. The differential characters described
by Germain and Joubin (1912, p. 6) are certainly such as to suggest
this synonymy and I find myself in agreement with Baldasseroni.

In the following keys seven genera are therefore recognized, of
which Sagitta is represented by 23 species, Eukrohnia by three,
Spadella by two, and each of the others by one: Pterosagitta draco
(see p. 264), HeteroJcroJinia mirabilis (Ritter-Zahony, 1911, p. 42),

238 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

KroJinitta subtilis (see p. 269), and KroJinitella loureei (Germain and
Joubin, 1912, p. 133).

KEY TO GENERA.

1. Two pairs of rows of teeth 2

1. Teeth entirely absent, or only one pair of rows present 4

2. Two pairs of lateral fins, the posterior pair being partly on body and partly

on tail. Fins completely or incompletely rayed; anterior and posterior
pairs sometimes connected by narrow membrane Sagitta.

2. One pair of lateral fins, or two pairs of which the posterior one is entirely

confined to the tail-segment. Fins completely rayed 3

3. One pair of lateral fins confined entirely to tail-segment. Collarette massive,

extending to tail-septum and spreading out over fins. Greatest width
slightly anterior to tail-septum, and exceeding half that of the body.
Ventral transverse muscles absent. Anterior and posterior teeth both

exceed six in number Pterosagitta.

3. One pair of lateral fins confined entirely to tail-segment, or two pairs the
posterior one of which is confined to tail-segment. Collarette present but
not massive. Greatest width slightly behind head, less than half that of
body. Ventral transverse muscles present in body-segment only. Neither
anterior or posterior teeth exceed five in number Spadella.

3. One pair of lateral fins partly on body and tail. Collarette absent. Ventral

transverse muscles present in both body and tail Heterokrohnia.

4. Lateral fin begins at or in front of ventral ganglion and extends onto tail but

never to seminal vesicles. Ventral transverse muscles present in anterior
third of body. One pair of rows of teeth EukroJinia.

4. Lateral fin begins about half-way between ventral ganglion and tail-septum,

and extends fully to seminal vesicles. Ventral transverse muscles absent. . 5

5. Head small but wider than body. Less than 50 per cent of fin in front of

tail-septum. Width of body less than 8 per cent of total length. One

pair of rows of teeth. Seizing jaws delicate, but not filliform Krohnitta

5. Head small, narrower than body. More than 60 per cent of fin in front of
tail-septum. Width of body exceeds 9 per cent of total length. Teeth
absent. Seizing jaws filliform Krohnittella.

KEY TO SPECIES OF SAGITTA.

1 . Collarette absent 2

1. Collarette present 13

2. Shaft of seizing jaw serrated S. serratodentata.

2. Shaft of seizing jaw not serrated 3

3. Anterior and posterior fins confluent 4

3. Anterior and posterior fins separated 5

4. Both pairs of fins entirely ray less throughout at least their anterior thirds;

tail usually exceeds 15 per cent of total length S. lyra.

4. Fins only rayless adjacent to body but not along outer margins; tail usually

less than 15 per cent of total length S. gazelle.

5. Anterior fins longer than posterior fins S. philippini.

5. Posterior fins longer than anterior fins 6

6. Anterior fins entirely rayless; rays of posterior fin perpendicular to body.

S. minima.

6. Anterior fins not entirely rayless; rays of posterior fin directed obliquely

to body 7

7. Anterior fins extend nearly if not quite to ventral ganglion 8

7. Anterior fins never extend within half their length of ventral ganglion 9

8. Both pairs of fins with rays throughout; mature ovary short and thick, not

reaching anterior limit of posterior fins S. setosa.

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS. 239

8. Anterior extremities of both pairs of fins rayless; anterior fin also rayless

throughout a narrow strip adjacent to body; mature ovary long and
narrow, extending nearly if not quite to ventral ganglion S. serratodentota

9. Tail 28-40 per cent of total length; posterior teeth 20-38, rarely as few as 17.

S. macrocephala.

9. Tail less than 28 per cent of total length; posterior teeth rarely exceed 16. . 10
10. Posterior fins extend nearly if not quite to seminal vesicles; both pairs of fins

rayed throughout 11

10. Posterior fins never extend more than § distance from tail-septum to

seminal vesicles; both pairs of fins rayless throughout a narrow strip
adjacent to body 12

11. Body very transparent; interval between anterior and posterior fins always

less than half the length of posterior fin S. setosa.

11. Body semi-translucent but never transparent; interval between anterior and

posterior fins usually greater than half the length of posterior fins S. elegans

12. Vestibular ridge composed entirely of papillae; anterior teeth 0-4, rarely 5;

posterior teeth 0-6 S. hexaptera,

12. Vestibular ridge provided with usual skeletal parts; anterior teeth 5-12,

rarely less than 6; posterior teeth 7-18, rarely less than 10 S. enflata.

13. Collarette short, not extending over half-way from neck to ventral ganglion. 14

13. Collarette long, extending more than £ distance from neck to ventral

ganglion 22

14. Anterior fins longer than posterior fins 15

14. Posterior fins longer than anterior fins 18

15. Posterior fins never extend nearly to seminal vesicles S. decipiens,

15. Posterior fins extend nearly if not quite to seminal vesicles 16

16. Body transparent; anterior fins exceed 30 per cent of total length of animal.

S. pulchra.

16. Body opaque or semi-translucent, but never transparent; anterior fine

less than 30 per cent of total length of animal 17

17. Both pairs of fins rayed throughout S. neglecta.

17. Anterior extremities of both pairs of fins rayless S. bedoti.

18. Interval between anterior fins and ventral ganglion exceeds one-fifth length

of fins S. bipunctata.

18. Anterior fins extend nearly if not quite to ventral ganglion 19

19. Collarette inconspicuous, extending less than one-fourth distance from

neck to ventral ganglion 20

19. Collarette well developed, extending between one-fourth and one-half

distance from neck to ventral ganglion 21

20. Pronounced constriction at tail-septum; sexually mature at a length of

5-6 rnm ." S. tennis

20. No constriction at tail-septum; never sexually mature under 9-10 mm.-S'./ncfenci.

21. Anterior teeth 10-18; exceeding number of posterior teeth S. helenae.

21. Anterior teeth 4-9; less than number of posterior teeth S. hispida.

22. Collarette never extending to ventral ganglion S. neglecta.

22. Collarette extending from neck to seminal vesicles S. caUfornica.

22. Collarette extending fully to ventral ganglion, frequently onto anterior fins,

but never beyond anterior quarter 23

23. Posterior fins longer than anterior fins S. regularis.

23. Anterior fins longer than posterior fins 24

24. Less than 50 per cent of posterior fin in front of tail-septum S. ferox.

24. More than 50 per cent of posterior fin in front of tail -septum S. planktonis.

KEY TO SPECIES OF SPADELLA.

1. One pair of lateral fins entirely on tail-segment. Ventral transverse muscles

present throughout entire body-segment S. cephaloptera.

240 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

1. Two pairs of lateral fins, the posterior pair much larger and confined entirely
to tail-segment, beginning directly behind seminal receptacle. Anterior
pair extends throughout posterior third of body, beginning directly in
front of seminal receptacles. Ventral transverse muscles present only in
anterior half of body S. schizoptera .

KEY TO SPECIES OF EUKROHNIA.

1. Anterior two-thirds of lateral fins rayless. Posterior extremity of fins less
than half-way from tail-septum to seminal vesicles. Width of body less
than 8 per cent of total length of animal. Seizing jaws delicate; some-
times serrated 2

1. Lateral fins delicately rayed throughout. Posterior extremity of fins at

least three-fourths way from tail-septum to seminal vesicles. Width of
body exceeds 12 per cent of total length of animal. Seizing jaws massive;
not serrated - ^ E. richardi.

2. Eyes without pigment. Seizing jaws 8-10, gently curved throughout.

Points sickle-shaped E. hamata.

2 Eye with pigment. Seizing jaws 11-13, sharply curved in anterior quarter.

Point slightly curved toward edge of jaw, but not sickle-shaped E.fowleri.

SPECIES OBTAINED DURING THE PHILIPPINE EXPEDITION.
Genus SAGITTA Quoy and Gaimard.

SAGITTA PHILIPPINI, new species.

Plate 34, figs. 1-4.

General appearance. — To the naked eye S. pJiilippini, when placed
in formalin upon a white background, appears white in color, scarcely
distinguishable from the background. Its head and tail, and in less
degree its ovaries, assume a brownish-yellow color in marked con-
trast to the body proper. On a black background the head, ventral
ganglion, ovaries, tail, seminal vesicles, and to a less extent the
intestine appear much more opaque than the body, which resembles
ground glass. The lateral fins and tail fin are so transparent as to be
invisible to the naked eye. In degree of opacity S. philippini
resembles 8. decipiens more than any other species, although it is
perhaps less transparent.

Characters. — Collarette absent. Neck conspicuous. Lateral fields
prominent. Body flabby, not retaining its form well; widest behind
center, tapering gradually forward toward head and backward
toward tail. No constriction at tail-septum. Ovaries, even when
immature (pi. 34, fig. 1), extend beyond posterior end of anterior fin.
Corona ciliata not observed.

Anterior fins (pi. 34, fig. 1) rayless throughout anterior half of fin.
They are longer and narrower than posterior fins, and extend ante-
riorly beyond posterior end of ventral ganglion. Form triangular,
the position of greatest width being in the caudal quarter of fin.
Interval from anterior to posterior fins slightly greater than maximum
width of body.

Posterior fins do not extend caudally to seminal vesicles. More
than 50 per cent of fin in front of tail-septum. Form triangular,
the position of greatest width being at or just behind tail-septum.

CHAETOGlSrATHA COLLECTED BY STEAMER ALBATROSS. 241

Vestibular ridge (pi. 34, fig. 3) well developed with large papillae.
Wing of ridge covers all but the first two or three teeth, the notch
extending to the fourth or fifth. External process long and blunt.

Anterior teeth (pi. 34, fig. 2), nine in number. They are short,
broad, closely set, and diverge but little distally.

Posterior teeth (pi. 34, fig. 3), 20 in number. They are long,
narrow, closely set, and diverge even less than do the anterior teeth.

Seizing jaws (pi. 34, fig. 4), six in number. Point with an oval
base imbedded between 20 and 25 per cent of its height into shaft.
Top of shaft and base of point converge toward edge of jaw. Edge
of shaft provided with narrow crest. Pulp canal central and slightly
swollen at base of point. Pulp evenly distributed.

Only a single specimen was obtained. Its measurements follow:

Length 13 mm.

Width 5. 5 per cent of length.

Length of tail 23 per cent of length.

Tip of tail to posterior end of ventral ganglion 70. 5 per cent of length.

Length of ventral ganglion 6. 5 per cent of length.

Length of posterior fin 22 per cent of length.

Width of posterior fin 4. 5 per cent of length.

Interval from anterior to posterior fins 6 per cent of length.

Per cent of posterior fin in front of tail-septum 60 per cent.

Length of anterior fin 30 per cent of length.

Width of anterior fin 2.5 per cent of length.

Anterior fin extends beyond posterior end of ventral ganglion

by 2 per cent of length.

Ovary extends beyond posterior end of posterior fin by 14 per cent of length.

Anterior teeth 9-9

Posterior teeth 20-(?)

Seizing jaws 6-6

The single specimen (Cat. No. 17801, U.S.N.M.) was taken from
the surface May 14, 1908, off Uanivan Island, at station D 5240,
latitude 6° 49.5' north and longitude 126° 15' east. The same haul
also yielded 130 S. enflata, 105. ferox, 6 S. Tiexaptera, 1 P. draco, and
75 S. decipiens.

8. pJiilippini bears a strong resemblance to the latter species, but
differs from it in several important details: In the first place, it has
no trace of a collarette, although this structure, while not pronounced
in S. decipiens^ is conspicuous. Again, the ovaries of S, philippini,
though not fully mature, extend nearly to the middle of the anterior
fin, while in 8. decipiens they do not, when mature, extend beyond
the anterior limit of the posterior fin. Further, the posterior fin of
S. philippini is rayed throughout, while in 8. decipiens (pi. 35, fig. 8)
the anterior fourth or fifth of the fin is rayless. Lastly, the seizing
jaws of the two species are quite different (pi. 34, fig. 4, and pi. 37,
fig. 22), the jaw in S. pMlippini being provided with a narrow but
conspicuous crest, which is missing in S. decipiens.

242 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

Altogether, these differences would seem to justify the description
of a new species, even though it may later prove to be synonymous
with S. decipiens. Had more than one individual been obtained, I
should feel certain of the validity of S. philippini, but as the matter
stands this single specimen might with as much justification be
regarded as an abnormal S. decipiens.

SAGITTA ENFLATA Grassi.

Plate 38, fig. 28.

Sagitta enflata GRASSI (1883), p. 13. — FOWLER (1906), p. 8. — RITTER-ZAHONY
(1911), p. 13.— MICHAEL (1911), p. 28.

This species is represented in the Philippine collection by approxi-
mately 2,800 individuals. They usually exceed 20 mm. in length,
and the largest taken measures 31.5 mm. In the San Diego region,
on the other hand, the specimens rarely exceed 18 mm. in length, the
largest recorded (Michael (1911, p. 29)) measuring only 21 mm.
Again, the anterior teeth number 6 to 11, typically 7 or 8, in the
Philippine specimens, while they number 4 to 8, typically 6 or 7, in
San Diego specimens. Similarly, the posterior teeth number 9 to 15
in the Philippine specimens, the usual number being 14, while they
number 6 to 12 hi San Diego specimens, the usual number being 10
or 11. In all other respects, however, specimens from the two
localities are in agreement, and the Philippine specimens agree in
size and number of teeth with specimens described by Fowler (1906
p. 8) from the Siboga region.

One puzzling fact is revealed by the Philippine collection. The
ovaries in most of the larger specimens are barely approaching
maturity, only one case of complete maturity having been discovered
in individuals exceeding 20 mm. in length; but among individuals
under 16 mm. in length many have mature ovaries (pi. 38, fig. 28).
In my San Diego report (1911, p. 56) a table is given of specimens of
S. enflata arranged in three groups according as their ovaries were
mature, approaching maturity, or remote from maturity. In the
first group the specimens varied in length between 12.5 and 19.5 mm.,
in the second between 15 and 17.5 mm., and in the third between 8
and 15.5 mm. Obviously, these facts are open to two interpretations:
First, the ovaries hi San Diego specimens attain maturity only once
and that after a length of 12 mm. is reached; and, second, the ovaries
in the same individual become mature periodically, first when the
individual is not less than 12 mm. in length, and subsequently after
it has grown larger. If the second interpretation is eliminated, how
is the relation between length of individual and stage of maturity of
the ovary in the Philippine specimens to be accounted for ? It could,
of course, be readily explained on the assumption that two species
had been confused, but I am unable to discover any other differences
even remotely indicative of more than one species. In Table 1, for

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS.

243

example, No. 9 alone had mature ovaries, but its measurements agree
with the other larger and immature specimens.

TABLE 1. — Measurements of Sagitta enflata.1

2.1.2
23. 7
23. 6
23.2
21.1
20.6
KS
IS. 4
15.8

is. a

10.2

10.7
10.7

8.7
10.4

9. 9
12.4
12.8
11.8
12.5

9.7

7.7

74.5
74

69.8
73

74.8

71.6

70. 4

73. C

71

71.7

72.3

Posterior fin.

17.T)

10.9

17.3

8.3

4.8

66.7
62.5
80.3

fi2

64.1

64.8

65

63.4

S3. 0

70

59.9

Anterior fin.

11.8
12.2
14.9
13.4
15. S
13.6
15.6
17.7
11.6
16.2
10.7

15.4
16.9

18.2

10-7
8-7
9-11

7- 7

8- 9

14-14
15-15

14-15
13-13

8-8
8-8
9-9

8-8
8-8
8-7
9-8
9-9
8-9
7-8

1 All measurements made in per cent of total length of animal.
' Per cent of posterior fin in front of tail-septum.

Distribution. — S. enflata was collected from 39 stations, or 85 per
cent of the 46 stations at which chaetognaths were taken, a total
of approximately 2,800 specimens having been obtained. Of the 39
stations 8, or 21 per cent, were mesoplanktonic, while 31, or 79 per
cent, were epiplanktonic, and 22, or 56 per cent, were surface stations.
From the 8 mesoplanktonic stations a total of 247 specimens was
obtained, or an average of 31 per station, while from the 31 epiplank-
tonic stations a total of 2,559 specimens, or an average of 83 per
station, was obtained, and from the 22 surface stations a total of
1,476 specimens, or an average of 67 per station, was obtained.
These data, together with the fact that all subsurface hauls were
made with open nets, make it clear that S. enflata occurs typically
in the upper epiplankton of the Philippine region.

The northernmost record of its capture during the Philippine expe-
dition is 14° 21 '.5 north and 120° 23 '.3 east in the China Sea near
southern Luzon. The southernmost record is 5° 36M south and
127° T. 6 east in Buton Strait. The easternmost and westernmost
records are 127° 44'.0 east and 1° 3'.0 south, south of Patiente Strait,
and 117° 53' east and 21° 31' north in the China Sea off Hongkong.
The largest number (950) was taken February 7, 1908, at 8.05 in the
morning from 25 fathoms by an open 0000 grit-gauze net towed
horizontally 9 fathoms above the bottom of the Sulu Archipelago,
near Basilan Island, at 6° 44'.2 north and 121° 47' east. Other
species taken in the same haul are: 318 S. bedoti, 217 8 ferox, 116
S. pulcJira, 2 S. Jiexaptera, and 19 P. draco. The complete records of
its capture are given in table 2 :

244 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

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CHAETOGNATHA COLLECTED BY STEAMEE ALBATROSS.

245

SAGITTA HEXAPTERA d'Orbigny.

Sagitta hexaptera D'ORBIGNY (1843), p. 140.— FOWLER (1906), p. 11.— RITTEE-
ZAHONY (1911), p. 7.— MICHAEL (1911), p. 30.

This species is the second most abundant and frequent obtained
during the Philippine expedition, being represented by approximately
700 specimens. Most are large though immature, the largest speci-
men measuring 45 mm. in length. Curiously, both anterior and
posterior teeth in many specimens are entirely missing. My first
impression was that although not seen they must be present, but
careful dissection of several heads has made it certain that the teeth
are actually missing. This was not noticed in San Diego specimens,
two being the smallest number of either anterior or posterior teeth
recorded in my (1911) report. Again, Fowler (1906, p. 13) lists the
number of teeth in 42 specimens, one being the smallest number of
either anterior or posterior teeth recorded. Ritter-Zahony (1908,
p. 10), however, while recording three as the smallest number of
anterior teeth, gives four instances in which the posterior teeth in
individuals 33, 34, 36, and 38 mm. in length were missing. In
attempting to account for the peculiar variability in number of teeth,
Fowler (1906, p. 14) explains their absence in the Philippine speci-
mens. He says:

I believe the explanation to lie mainly (perhaps not entirely) in the length and
slenderness of the teeth; many of them are probably torn out by the roots; certainly
many are broken off short, for their bases may be seen still in place. As an additional
weakness, the posterior teeth in older specimens often appear not to be attached to the
bony bar with which they are united in other species, but to lie at some distance from
it in a superficial plate of chitinous material.

TABLE 3. — Measurements of Sagitta hexaptera.1

17.0 65.1

19.1 65.8
19.1 72

10.6 14.5

9.6! 15.51 3.3

11.8! 11.2 2.3

7.2 14.31 2

14.1 1 15.2 2.1

6.9l 13.6! 3
10. o! 2.3

14.9; 39.2 .62-16

14.6 55. 51 2.16+ 4.2

11.8 19.7; 1.09-23.2

11.4 24. 5i 1.12; -19.1

-21.6
.46; -32. 3
.46-
.711-27
1. 311-12. 4

All measurements made in per cent of total length of animal.
Per cent of posterior fin in front of tail-septum.

The + signifies extension beyond anterior end of ganglion; the — signifies distance from posterior end
of ganglion.

246 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

Distribution. — S. Jiexaptera was collected from 26, or 57 per cent, of
those stations at which chaetognaths were captured. Of these, 8
were mesoplanktonic, while 13, or one-half, were surface stations.
From the 8 mesoplanktonic stations a total of only 70, or an average
of 9 to each station, was obtained, while the 18 epiplanktonic stations
yielded 642, or an average of 36 per station, and the 13 surface sta-
tions yielded 491, or an average of 38 per station. It is evident,
therefore, that S. Jiexaptera occurs typically in the upper epiplankton
of the Philippine region.

S. Jiexaptera, often confused with S. elegans and with the large
variety (S. maxima) of 8. lyra, is a eurythermal, nearly cosmopolitan
species found typically in the lower epiplankton and mesoplankton
of the arctic, sub-arctic, north temperate, tropical, and south tropical
Atlantic, the south temperate and tropical Indo-Australian, and the
north temperate and sub-antarctic Pacific oceans. Its northern and
southern limits of distribution are 74° north and 28° south, while
the extremes of temperature recorded in connection with its capture
are 29° C. and 6° C. A statement frequently encountered in the
literature is that surface Chaetognatha of the arctic seas would be
found, if at all, in the mesoplankton of temperate and tropical
regions, the implication being that temperature plays the all-
important part in delimiting the vertical distribution of a species.
Obviously, the typical occurrence of S. Jiexaptera in the upper epi-
plankton during the Philippine expedition contradicts this statement,
which contradiction is further supported by Ritter-Zahony (1911,
p. 54), who says: "Es gibt keinen einzigen verbiirgten Fundort der
8. Jiexaptera aus dem Epiplankton der Meere nordlich von 40° N."
Rather do the facts point in quite the opposite direction, that is
that surface 8. Jiexaptera of tropical and sub-tropical regions are
found, if at all, hi the lower epiplankton and mesoplankton of arctic
and sub-arctic regions. However, until consistency of identifica-
tion of the species obtained during the various expeditions is attained,
and until the vertical distribution of the species in diversified regions
is critically studied, no conclusion as to the part played by tempera-
ture or any other environmental influence, in controlling its distri-
bution throughout the world, is justified.

The northernmost and westernmost record of its capture during
the Philippine expedition is 21° 31' north and 117° 53' east in the
China Sea, off Hongkong. Its southernmost record is 5° 36 M south
and 122° 7'.6 east, in Buton Strait; and its easternmost record is
127° 44' east and 1° 3' south, south of Patiente Strait. The largest
number (153 + ) was taken August 11, 1909, at 7.49 in the evening,
from the surface between Siquijor and Bohol Islands, at 9° 2 7 '.5
north and 123° 38' east. Other species obtained at the same station
are: 169 8. enflata, 128 S. pulcJira, 50 S.ferox, and 14 S. bedoti.

CHAETOGtfATHA COLLECTED BY STEAMER ALBATROSS. 247

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248 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

SAGITTA MINIMA Grass!.

Plate 37, figs. 16-17; plate 38, fig. 29.
Sayitta minima GRASSI (1881), p. 213; (1883), p. 15.— KRUMBACH (1903), p. 637.-

RlTTER-ZAHONT (1911), p. 25.

This species is represented by only two specimens (Cat. No. 17925,
U.S.N.M.), both of which are apparently sexually mature. Both
were obtained on April 3, 1908, from the surface at station D. 5195,
off northern Cebu Island, 10° 47' north and 124° 6'.5 east. Except
for the mature ovaries they are almost inseparable to the naked
eye from small S. enfiata. Microscopic examination, however,
reveals several marked differences. The species is redescribed on
the basis of these two specimens.

Collarette absent. Body flabby and widest on a level with anterior
end of posterior fins, tapering gradually toward head and tail. Con-
striction at tail-septum slight or absent. Ovary (pi. 38, fig. 29)
short, not extending to anterior end of posterior fins. Ova large
and arranged in a single row within the ovary. Corona ciliata not
observed.

Anterior fins shorter and narrower than posterior fins and entirely
rayless. They fall short of reaching the posterior end of ventral
ganglion by nearly two-thirds the length of fins. Interval from
anterior to posterior fins approximately equal to half the length of
anterior fins.

Posterior fins (pi. 38, fig. 29) with rays arranged perpendicular
to the body. Interval from fins to seminal vesicles 3 to 5 per cent
of total length. More than 50 per cent of fins in front of tail-septum.
Position of greatest width behind tail-septum.

Vestilular ridge (pi. 37, fig. 16) provided with low, regular papillae,
one for each tooth. Wing covers all except the first tooth, the second
being just barely covered. Notch extends to fourth tooth. Ex-
ternal process apparently missing.

Anterior teeth, 4 to 5 in number (2 to 5 according to Ritter-Zahony,
1911, p. 26). They are very closely set and not diverging much
distally. Posterior teeth (pi. 37, fig. 16), 10 or 11 in number (6 to 14
according to Ritter-Zahony). They are not so closely set as the
anterior teeth, but are more divergent distally.

Seizing jaws (pi. 37, fig. 17), 8 or 9 in number (7 to 8 according to
Ritter-Zahony). Point with an oval base, inserted into shaft by
less than one-fifth its height. Tip of point curved toward its edge.
Base of point and top of shaft parallel. Pulp-canal central, with a
swollen place below base of point. Pulp evenly distributed through-
out canal.

Aside from the number of teeth and seizing jaws and length of
tail, only one of the two specimens is well enough preserved to permit
accurate measurements.

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS.

249

Length in mm 9. 5.

Tail:

Length 20. 8 per cent of length .

To ventral ganglion 68. 5 per cent of length.

Posterior fin :

Length 17. 6 per cent of length .

To seminal vesicles 3. 2 per cent of length.

To anterior fin 9. 1 per cent of length.

Proportion in front of tail-septum 59. 1 per cent.

Anterior fin:

Length 16. 5 per cent of length.

To ventral ganglion 11. 7 per cent of length.

Number of anterior teeth. . . : 5-4.

Number of posterior teeth ll-(?)

Number of seizing jaws 8-9.

The other specimen measured 8.9 mm.; its tail measured 20.7 per
cent; the number of anterior teeth are 4-5; the number of posterior
teeth, 10-10; and the number of seizing jaws, 9-8.

SAGITTA SERRATODENTATA Krohn.

Sagitta serratodentata KROHN (1853), p. 272. — FOWLER (1905), p. 58. — HITTER
ZAHONY (1911), p. 22.— MICHAEL (1911), p. 39.

Approximately 100 specimens were obtained, none of which is
sexually mature. The number of anterior and posterior teeth is
greater than recorded by Fowler (1905, p. 58) in specimens taken
from the Bay of Biscay, or by myself (1911, p. 40) in specimens taken
from the San Diego region. In specimens between 7 and 11 mm. in
length Fowler records 3 to 6 anterior and 2 to 10 posterior teeth,
while in Philippine specimens between the same lengths, the anterior
teeth number 8 to 11 and the posterior teeth 13 to 24. The San
Diego specimens are considerably larger, those recorded varying in
length between 10 and 17 mm.; but the number of teeth is inter-
mediate, the anterior teeth numbering 6 to 9 and the posterior teeth
13 to 19. The species appears to be unusually variable.
TABLE 5. — Measurements of Sagitta serratodentata.1

10. 5
10.3
10.2

20.0

24

SB

90

24.5
9B

2:.. 5

27

25.5

Posterior fin.

Anterior fin.

20. 0

28

27

27.5
SI
28
28. fl

51.5

55

52

52

50.5

50

49.5

52

55

IS. 5
22.5
21

22
21.5

10-10 23-22

11-11 24-23

11-10 20-18

8 -9 20-?

9 -8
9 -9

9 -8 15-14

9 -9 18-19

9 -? 15-?

9 -9 14-13

17-16

.

o>

6-5
6-6
6-6
6-6
6-6
7-7
0-6
6-7
6-1
7-7

1 All measurements made in per cent of total length of animal.
i Per cent of posterior fin in front of tail-septum.

59318— 19— Bull. 100 2

250

BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

< i-l 0* Oi iO r-teO

a a a a a a a a

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Distribution. — S. serratodentata was
collected from only eight stations. All
except three were mesoplanktonic, but
the largest number of specimens (73)
were taken from the surface. The rec-
ords are given in Table 6 :

SAGITTA MACROCEPHALA Fowler.

Sagitta macrocephala FOWLER (1905), p. 65. —
RITTER-ZAHONY (1911), p. 31.

A single distorted specimen was ob-
tained. Its measurements follow:

Length in mm 7.8 mm.

Width in per cent of length 14.4 per cent.

Tail in per cent of length 37. 4 per cent.

Length of posterior fin 24. 8 per cent.

Per cent of fin in frontof tail-
septum 45.5 percent.

Width of posterior fin 7 . 7 per cent.

Interval from anterior to posterior
fin 5.5 per cent.

Length of anterior fin 15.0 per cent.

Width of anterior fin 2. 7 per cent.

Number of anterior teeth 7-7

Number of posterior teeth 25-26

Number of seizing jaws 11-11

Ventral ganglion, corona ciliata, and
ovaries not observed.

The specimen differs conspicuously
in width from those drawn by Fowler
(1905, pi. 5, fig. 16) and Ritter-Zahony
(1911, fig. 37). In width the Philip-
pine specimen measures 14.4 per cent
of the length, while Fowler draws it
7.8 per cent, and Ritter-Zahony 5 per
cent. However, the Philippine specimen
is clearly immature, neither ovaries nor
seminal vesicles being visible. More-
over, it is poorly preserved, some
portions of the body being distorted
and others torn away. These facts
are probably responsible for the ex-
cessive width. Unfortunately the points
of all' seizing jaws were broken off,
so that their structure could not be
determined.

CHAETOGNATHA COLLECTED BY STEAMER, ALBATROSS. 251

The single specimen (Cat. No. 17926, U.S.N.M.) was obtained
November 6, 1908, in the China Sea, in the vicinity of Formosa, at
station D. 5320, 20° 58' north and 120° 3' east by an open 0000 grit
gauze net towed at 3.18 in the afternoon in 500 fathoms for twenty
minutes.

SAGITTA PULCHRA Doncaster.

Plate 35, fig. 5; plate 37, figs. 19, 23.

Sagitta pulchra DONCASTER (1902), p. 213.— FOWLER (1906), p. 17.— RITTER-
ZAHONY (1911), p. 21.

Approximately 500 individuals were obtained, and few, if any, are
sexually mature. In body length and number of teeth they agree
remarkably well with specimens described by Fowler (1906) from the
Siboga region. He records 5 to 10 anterior and 9 to 15 posterior
teeth in specimens between 9 and 22 mm. in length, and in Philippine
specimens between 9 and 30 mm. in length, the anterior teeth number
5 to 9, and the posterior teeth 10 to 13. The Philippine specimens
are, on the whole, so well preserved that the species is redescribed.

Collarette (pi. 35, fig. 5) conspicuous but short, varying in length
from one-twentieth to one-tenth the length of the animal. Its
length is less than twice the body width and it extends between one-
fourth and one-half the distance from neck to ventral ganglion Neck
pronounced but rendered inconspicuous by the collarette. Muscles
thin but strong. Lateral fields large. More transparent than any
other species having a collarette, and similar in transparency to S.
enflata. Its body, however, is firmer than that of 8. enflata and is
approximately half as wide. Width greatest between one-half and
three-quarters the distance from head to tail-septum, tapering
gradually forward and more rapidly backward. Slight constriction
at tail-septum. Tail 18 to 25 per cent of total length of animal.
Corona ciliata not observed.

Anterior fins (pi. 35, fig. 5) longer and narrower than posterior fins
extending anteriorly beyond posterior end of ventral ganglion,
frequently beyond its middle, and rarely beyond its anterior end.
No rays except in posterior quarter of fin. Interval from anterior
to posterior fins usually less than two-thirds width of body, varying
from slightly less than one-half to slightly more than the width.

Posterior fins (pi. 35, fig. 5) rayless anteriorly. They extend
posteriorly nearly if not quite to seminal vesicles, the interval
never exceeding 2.5 per cent of total length of animal. More than
50 per cent of fin in front of tail-septum, varying from 50.5 to 64 per
cent. Broadly triangular in form, and widest at or slightly behind
tail-septum.

Vestibular ridge (pi. 37, fig. 19) provided with large regular papillae,
the apices of which usually terminate in two minute spines. Wing
of ridge covers all except first two or three teeth. Notch extends

252

BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

to fourth or fifth tooth. External process one-third to one-half
length of ridge and approximately four times longer than broad.

Anterior teeth 5 to 9, closely set and diverging distally. Posterior
teeth (pi. 37, fig. 19) 10 to 13, not so closely set nor so divergent dis-
tally as anterior teeth.

Seizing jaws (pi. 37, fig. 23) 5 to 6 in number. Point with oval
base inserted little more than one-tenth its height into shaft. Base
of point and top of shaft parallel. Edge of shaft provided with
broad thin crest. Pulp-canal central, with pulp evenly distributed
throughout.

TABLE 7. — Measurements of Sagitta pukhra.1

19. r,

5.5 18
7 17.5
6. j 19.5
5.5! 19.5!

6 I 20
5.5| 21
6 I 19.5
5.5! 21
20

70

72

71

70.5

71)

72

71

70. 5

67

eg

li

Posterior flu.

Anterior fin.

2.5 64 37.5
3.5 56 ! 37.5
2.5! 63.5 36

2 i 58. 5' 36

3 I 59.5 32
1.5: 56.5 35
4.5 59.5i 33.5
7 54 | 32.5
3 58. 5! 36
4.5 55.51 33
3.5 60 I 32

0 ' 56 32

62 i 32
51.1 31.5

1 I 50.5f 32

+4.5
2.5 +1
2.5j +1.5
3 +1.5

2 + .5
3.5 +2
3.51 +1.5
2.5 + .5

3 | +1.5

+1.5
+2.5

Collar-
ette.

+3.5!

+2

+2

10-10
11-12
12-13

0-7

Mi

M

7-6 10-11

7-8! 10-11

6-6

8-8

13-13
12-12
12-13

11-12
10- 9

i All measurements made in \

* Per cent of posterior fin in front of tail-septum.

Distribution. — S. pulchra was collected from 23 stations, or from
exactly 50 per cent of those at which chaetognaths were taken. Of
these only 5 were mesoplanktonic stations, and 14 of the remaining
18 were surface stations. There can be no question, therefore, that
the species is typical of the upper epiplankton in the Philippine region.
Its northernmost record of capture during the Philippine expedition
is in the China Sea, near Hongkong, 20° 58' north and 120° 3' east;
its southernmost record is in Buton Strait, 5° 36.1' south and 122°
7.6' east; its easternmost record is in the Gulf of Tomini, Celebes,
125° 17.1' east and 1° 13.2' north; and its westernmost record is in
Macassar Strait, 118° 50' east and 2° 19.5' south. The largest
number (128 + ) was taken August 11, 1909, at 7.49 in the after-
noon by a 0000 grit-gauze net towed on the surface between Siquijor
and Bohol Islands, at 9° 27.5' north and 123° 38' east. Other
species taken at the same station are S. enflata (169), S. lyra (85),
S.ferox (50), and S. bedoti (14).

CHAETOGXATHA COLLECTED BY STEAMER ALBATROSS. 253

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254 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

SAGITTA DECIPIENS Fowler.

Plate 35, fig. 8; plate 37, figs. 18,22.

Sagitta dedpiens FOWLER (1905), p. 70.— RITTER-ZAHONY (1911), p. 27.
Sagitta sibogae FOWLER (1906), p. 21. — RITTER-ZAHONY (1909a), p. 5. — MICHAEL
(1911), p. 74.

According to Ritter-Zahony (1911, p. 29), there is "keine spezi-
fischen Unterschiede in Fowler's Diagnosen und Abbildungen der
beiden Arten [8. dedpiens und S. sibogae] und S. sibogae weist
danach — als alteres Stadium ! — gegeniiber S. dedpiens eigentlich nur
bedeutendre Dimensionen und hohere Zahlen fiir die Voider- und
Hinterzahne auf."

Although the species is represented in the Philippine collection
by more than 100 specimens, few are well enough preserved to permit
accurate measurements and their identification is therefore not
certain. They have more anterior and posterior teeth than recorded
by Fowler (1905, p. 70) in his original description, 8 to 11 anterior
and 19 to 22 posterior teeth against his records of 5 to 10 anterior and
12 to 18 posterior teeth. They agree, however, with his (19,06, p. 21)
records for S. sibogae, in which the anterior teeth number 7 to 10 and
the posterior teeth 13 to 23. They also agree, not so well perhaps,
with Ritter-Zahony's (1911, p. 28) records. He gives the number
of anterior teeth as 7 to 9 and the number of posterior teeth as 12 to
20. The species is redescribed on the basis of the Philippine material.

Collarette (pi. 35, fig. 8) inconspicuous, varying in length from
slightly less than one-quarter to slightly more than half the body
width. Body flabby, seldom retaining its form well, and widest on
level with posterior end of anterior fins) tapering gradually toward
head and tail. No constriction at tail-septum. Ovary short, not
extending beyond anterior limit of posterior fins. Corona ciliata
not observed.

Anterior fins (pi. 35, fig. 8) rayless throughout anterior half,
longer and narrower than posterior fins, and extending slightly
beyond posterior end of ventral ganglion. Interval from anterior
to posterior fins about equal to maximum width of body.

Posterior fins (pi. 35, fig. 8) rayless in anterior extremity. They
never extend posteriorly to seminal vesicles, the interval varying in
length from about 25 to 110 per cent of the maximum body width.
More than 50 per cent of fin in front of tail-septum, varying from 54
to 65 per cent. Form irregular, the position of greatest width being
at or just behind tail-septum.

Vestibular ridge (pi. 37, fig. 18) concealed by a thick cuticle. It
is characterized by large fairly regular papillae extending internally
beyond the teeth and terminating near the mouth. Whig covers
all except the first one or two teeth, the notch extending to the
third or fourth. External process not observed. According to

CHAETOGNATHA COLLECTED BY STEAMER ALBATEOSS.

255

Fowler (1905, p. 70) it is "a very strong process; sometimes forked
at the external edge."

Anterior teeth 8 to 11, short, broad, and diverging distally. Pos-
terior teeth 19 to 22, longer, and more closely set than anterior teeth.

Seizing jaws (pi. 37, fig. 22), 5 to 7. Point inserted slightly less
than one-third its height into shaft, with an irregular triangular
projection at the middle of its base. Base of point and top of shaft
converge toward edge of jaw. Edge of point and edge of shaft on a
line with each other, but back of point and back of shaft intersect
each other, forming an obtuse angle. Tip of point slightly bent
toward edge of jaw. Pulp-canal displaced slightly toward back of
shaft, with a swollen place below base of point. Pulp evenly dis-
tributed throughout canal.

TABLE 9. — Measurements of Sagitta decipiens.1

§

1

I

Posterior fin.

Anterior fin.

Collarette.

1

.c

j

!

&

1

4

|

1

fe

I

UIUIUl

1
"3

1

1

•s

1

"a

|

a

<C3

I

1
1

1
J

"5

•5

*o

_2

S

A

£

3

tl

5

fl

§**

I

•S,

.g

g

S3

§

ji

A

j§

s
fc

1

3
^

1

I

s

1

2
£

1

g

S

2
^

g

I

g

i,

fc

|

1

2

12.4
12.2

5.0| 23.5
5.5 24

70.5 7.0: 20.0
67 1 9.5 20.5

4.0
5

5.5

4.5

7.5
6

64.5
fi5

27.0

98

1.5

2.5

+1.0

+ 1.5

3.0
3

15.5
15.5

9-8
9-9

19-20
21-20

6-«

6-6

3

11

5.5! 25

72.5 8.5 21.5

4.5

1 5

4

5S 5

W

2 (+1.5

1.5

13

10-11

22-22 5-5

4

9.1 (?)

?5. 5

70 i 8.5 24

5

2.5

4.5

55

27

2.5 +1.5

1.5

14

11-1C

19-21 7-7

5

8.8

5

24

69.5

8

22.5

(?)

2.5

3

58

28

2

+2

1.5

15.5 9-8

20-21

6-6

1 All measurements made in per cent of total length of animal.
* Per cent of posterior fin in front of tail-septum.

Distribution. — 8. decipiens was collected from only six stations,
four of which were mesoplanktonic and two surface stations.
According to the literature the species is typically mesoplanktonic,
only the very young having been taken above 100 fathoms. Its
records of occurrence during the Philippine expedition are given in
Table 10.

SAGITTA BEDOTI Bgraneck.

Plate 35, fig. 6; plate 37, figs. 20, 24; plate 38, fig. 30.

Sagitta bedoti BERANECK (1895), p. 137.— FOWLER (1906), pp. 6-8.— RITTER-
ZAHONY (1911), p. 20.— MICHAEL (1911), p. 75.

According to Fowler (1906, p. 6) 8. bedoti has "a very slight
thickening of the epidermis at the neck, but no real collarette."
In my 1911 report those species not taken from the San Diego
region were briefly described and, not having seen S. bedoti, I as-
sumed Fowler's statement to be correct and placed this species
among those in which the collarette was absent. Subsequently,
however, Kitter-Zahony's (1911) report appeared in which he (p. 20)

256

BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

II

So1

aasa

a B a a a a

'ZKttK'Z,

says: "Collerette relativ kurz, nur bis etwa
zur halben Corona reichend." The speci-
mens collected during the Philippine expedi-
tion agree with Ritter-Zahony's statement.
Every specimen has a collarette which,
while narrow and short, is broader and longer
than that of S. bipunctata. Owing to this
confusion in the literature, S. ledoti is
redescribed from the Philippine speci-
mens:

Collarette (pi. 38, fig. 30) conspicuous but
short, extending caudally a distance nearly
equal to greatest width of body. Head
small. Lateral fields large. Muscles strong,
but narrow. Body firm, retaining its form
well, widest slightly behind its middle, and
tapering gradually toward head and more
rapidly toward tail. No constriction at
tail-septum. Tail 20 to 30 per cent of total
length of animal. Corona ciliata not ob-
served.

Anterior fins (pi. 35, fig. 6) longer and
narrower than posterior fins, without rays
in the anterior half or two- thirds. Fins
extend nearly if not quite to posterior end
of ventral ganglion, the exact limit being
difficult to determine owing to absence of
rays. In some individuals the fins may
extend beyond posterior end of ganglion,
but never to its anterior end. Form acutely
triangular, the position of greatest width
being in posterior quarter of fins.

Posterior fins (pi. 35, fig. 6) extend
caudally to seminal vesicles. Rays absent
in anterior extremity. Usually, but not
always, less than 50 per cent of fin in
front of tail-septum, the extremes being
40 and 52 per cent. Triangular in form,
the position of greatest width behi'j; behind
tail-septum. Interval from anterior to
posterior fins varies from hah' to twice the
maximum width of body.

Vestibular ridge (pi. 37, fig. 2o)- promi-
nent and provided with regular and un-
usually acute papillae. Number of papillae

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS.

257

less than number of teeth. Wing of ridge covers all except the
first and occasionally the second tooth. Notch extends to the
fourth or fifth tooth. External process short and blunt, not, as
described by Fowler (1906, p. 6), "terminating externally in a well-
marked, rather sharp process." Its length is about two-sevenths
that of entire ridge.

Anterior teeth 8 to 10 and posterior teeth (pi. 37, fig. 20) 20 to 28
in number in individuals 10 to 15 mm. long. Anterior teeth are
closely set and diverging distally, while the posterior teeth are more
closely set and only slightly divergent distally.

Seizing jaws (pi. 37, fig. 24) 5 to 7 in number. Points with curved
tip, oval bases, and embedded about 25 per cent of then- heights
into shaft. Base of point and top of shaft parallel. Pulp-canal
central, extending into point about 75 per cent of its height and
converging markedly toward edge of point. Pulp evenly distributed
throughout canal.

TABLE 11. — Measurements of Sagitta bedoti.1

i S

° I

29 0
25

25

25. r.

25
20

25.

eg

24.7 4.0

24 4.5

27 3

23.5 4
26

14.4
16
14.5
, 15
14
16
15.5
16.5
16.5
15.5

9-10
9-9
9-10
S-9

24-22
24-23
27-28
22-21J
24-25!
25-24
22-21
24-25
23-22i

20-21;

1 All measurements made in per cent of total length of animal.

2 Ter cent of posterior fin in front of tail-septum.

Distribution. — S. ~bedoti was collected from only four stations, 352
specimens having been obtained. As shown by the following table
all specimens were taken from the upper epiplankton. This indica-
tion that the species typically occurs near the surface is supported
by other expeditions and collections. It has been taken near the
surface in the region of Port Natal by the Gauss expedition; in the
Maldive and Laccadive Archipelagoes by Doncaster (1902) under the
name S. polyodon; in the Malay Archipelago by Beraneck (1895) ;
in the Siboga region by Fowler (1906) ; in Misaki Harbor, Japan, by
Aida (1897) under the name S. lipunctata; and in Sharks Bay,
Australia, by Ritter-Zahony (1910). Altogether, the evidence war-
rants concluding that S. 'bedoti is characteristic of the upper epi-
plankton of the tropical Indo-Pacific region.

258

BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

'

•s.

SAGITTA NEGLECTA Aida.

Plate 35, fig. 9.

Sagitta neglecta AIDA (1897), p. 16. — FOWLER (1906), p. 15. —
RITTER-ZAHONY (1911), p. 23.— MICHAEL (1911), p.
46.

This species is represented by approximately 425.
specimens (Cat. No. 17927, U.S.N.M.), many of which
are mature. Curiously enough, all were taken by a
single surface haul on November 22, 1909, in Molucca
Passage at station D. 5615, 0° 32.5' south and 126°
31.5' east. Certain specimens obtained from five or
six other stations were at first thought to be 8. neglecta,
but closer examinations proved them to be either
young 8. serratodentata or 8. ledoti.

As in so many other cases, the Philippine specimens
have more anterior and posterior teeth than those
described from the San Diego region. In my former
(1911, p. 48) report, the number of anterior teeth is
given as 3 to 5 and the posterior teeth as 8 to 1 1 in in-
dividuals between 8 and 13 mm. in length. The
Philippine specimens, however, are smaller, ranging
as a rule between 6.5 and 8 mm. and the number of
anterior arid posterior teeth are 4 to 8 and 12 to 16,
respectively. This agrees better with Fowler's (1906,
p. 16) records for specimens from the Siboga region.
He records 3 to 7 anterior and 7 to 15 posterior
teeth in individuals between 5 and 10 mm. in length.
Similarly, Ritter-Zahony (1911, p. 24) records 5 to 7
anterior and 11 to 18 posterior teeth in individuals
from Port Natal between 6 and 7.5 mm. in length.
TABLE 13. — Measurements of Sagitta neglecta.1

18

28

37.5

47

57

67

77

87

5.f>:',2

Posterior fin.

Anterior fin

25
23.52

22.52.5
2

40
10

37.520.52
24

24

2.5

All measurements made in per cent of total length of animal.
1 Per cent of posterior fin in front of tail-septum.

CHAETOGNATHA COLLECTED BY STEAMEE ALBATEOSS. 259
SAGITTA FEROX Doncaster.

Plate 35, fig. 7; plate 37, figs. 21, 25.

Sagitta ferox DONCASTER (1902), p. 212.— FOWLER (1906), p. 10.— MICHAEL (1911),
p. 74.

Sagitta robusta (part) RITTER-ZAHONY (1909a), p. 49; (1911), p. 16.
Kitter-Zahony (1909a, 1911) synonymises this species to S. ro-
busta Doncaster and says (1909a, p. 49): "Ich glaube daher nicht
fehlzugehen, wenn ich mich fur die schon von Doncaster (1902,
p. 212) als moglich hingestellte Identitat dieser beiden Arten auspreche
und S. ferox nur eine altere S. robusta auffasse." Yet, although the
two species closely resemble each other, the Philippine specimens
do not indicate the slightest convergence with age in three important
differential characters (see Table 14):

1 . The collarette is much wider in 8. ferox and nearly always extends
beyond the anterior end of the ventral ganglion, while in S. robusta
it never extends much over halfway from neck to ventral ganglion.

2. Anterior fins always extend beyond posterior end of ventral
ganglion in S. ferox, while in S. robusta there is an interval between
the fins and ganglion.

3. Anterior fins are longer than posterior fins in S. ferox, while the
posterior fins are the longer in S. robusta.

These three persistent differences justify considering S. ferox
valid until critical study of variations in these particulars can be
made. The species is therefore redescribed from the Philippine
specimens in hopes that this description may aid in establishing
its valid or synonymical position:

Collarette (pi. 35, fig. 7) long and broad, extending past anterior
end of ventral ganglion onto anterior fins. Head large. Lateral
fields small. Body firm, opaque, and nearly of uniform width from
in front of ventral ganglion to tail-septum. Tail 25 to 30 per cent
of total length of animal. Corona ciliata not observed.

Anterior fins (pi. 35, fig. 7) longer and slightly narrower than
posterior fins, always extending anteriorly beyond posterior end of
ventral ganglion, frequently past its middle and occasionally to its
anterior end. Form acutely triangular, the position of greatest
width being in posterior quarter of fin.

Posterior fins (pi. 35, fig. 7) extend caudally to seminal vesicles.
Interval from anterior to posterior fins 3 to 7, usually about 5 per
cent of total length of animal. Less than 50 per cent (41 to 44) of
fin in front of tail-septum. Triangular in form, the position of
greatest width being about midway between tail-septum and seminal
vesicles.

Vestibular ridge (pi. 37, fig. 21) strongly mamillated, the number
of papillae corresponding to the number of teeth. Wing of ridge
covers all except the first two teeth, the notch extending beyond
the fourth or fifth. External process short, broad, and blunt.

260

BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

Anterior teeth 5 to 9 in number. They are closely set, provided
with broad bases, and diverging distally.

Posterior teeth (pi. 37, fig. 21) 10 to 14 in number. They are long,
broad, closely set, and diverging distally.

Seizing jaws (pi. 37, fig. 25) 4 to 6 in number. Point with an
oval base inserted into shaft between 15 and 20 per cent of its height.
Base of point and top of shaft converge toward back of shaft. Edge
of shaft provided with narrow crest. Pulp-canal central, and extend-
ing into point about 80 per cent of its height. Pulp evenly dis-
tributed throughout canal.

TABLE 14. — Measurements of Sagittaferox.1

Posterior fin.

Anterior fin.

+3.5
+4
+4
+5.5

Collarette.

+3

+2

+1

+2

+3.5

+4

+3

13-13
12-11

13-13 6-5

13-12 5-5

13-14 5-4

15-12 I 5-6

12-12 5-4

12-12 ; 5-5

12-12 5-1

12-12 ' 5-5

12-? 5-5

10-12 5-5

i All measurements made in per cent of total length of animal.

1 Per cent of posterior fin in front of tail-septum.

» The + indicates that the fin extends beyond posterior end of ganglion.

« The + indicates that the collarette extends beyond anterior end of ganglion.

Distribution. — 8. ferox was collected from 22 of the 46 stations
from which chaetognaths were taken, 598 specimens being obtained.
It is difficult to decide whether the species is typically epiplanktonic
or mesoplanktonic in the Philippine region. At 15 stations it was
taken from above 100 fathoms. Five, or 33 per cent of the epiplank-
tonic hauls, and two, or 29 per cent of the mesoplanktonic hauls,
obtained more than the average number of specimens (27). Again,
the median number of those taken above 100 fathoms is nine, but
nine is also the median number of those taken below 100 fathoms.
Finally, the greatest number was taken from 25 fathoms, the second,
fhird, and fourth greatest from the surface, and the fifth greatest
trom 500 fathoms.

All subsurface hauls, however, were made by various types of open
nets. It is well to remember that such hauls, whether horizontal or
vertical, afford no certain evidence of the depth from which specimens

CHAETOGNATHA COLLECTED BY STEAMER ALBATBOSS. 261

were collected. This is true even when every haul is made with the
same net, and when various types of nets are used the data are worse
than useless for this purpose. For these reasons it may well be
that, as indicated by other reports, S.ferox is typically epipianktonic
in the Philippine region. It was taken in abundance during the
Siboga expedition from the surface, but only rarely from the
mesoplankton.

Indeed the species appears to be restricted to the epiplankton of
the Indo-Australian region, although, owing to its questionable
synonymy with S. robusta Doncaster, this statement is made with
some reservations. But, even assuming the two species to be synony-
mical, it is still restricted in distribution to the surface and upper
epiplankton of tropical and subtropical regions. Thus, according
to Ritter-Zahony (1911, p. 58), it is found "im Atlantischen Ozean
zwischen 0° and 20° N., im Indischen zwischen 20° and 30° S. in
Vertikalfangen und an der Oberflasche. ..." He continues:
"Auf der Westseite des Atlantischen Ozeans wird sie zwar durch
den Floridastrom wohl bis in die Gegend des 40° N. gebracht, auf
der Ostseite gelangt sie jedoch kaum bis zum 35°. Breitegrad, da
sie ja schon im Mittelmeer fehlt. Im Siiden diirfte sie gerade noch
um die Siidspitze Afrikas herumkommen. Im Stillen Ozean ist
sie bisher nur funf Fundorten, die samtlich auf seiner Westseite
liegen, bekannt geworden. . . . Ich glaube jedoch, dass die Ver-
breitung der S. robusta im Stillen Ozean der im Atlantischen vollig
analog ist, d. h. das tropisch-subtropische Gebeit umfasst und nur
auf der Westseite etwas weiter nach Norden reicht, wobei der Kuro-
Siwo die Rolle des Floridastroms uberniinmt." Clearly S. ferox
is a warm water species, but is its absence hi the eastern Pacific
not more likely attributable to the abnormally cold water there
due to upwelling? (see p. 271).

The northernmost and westernmost record of its capture in the
Philippine region is 21° 31' north and 117° 53' east, or in the south
China Sea, approximately halfway between the city of Hongkong
and the island of Formosa. The southernmost record is 5° 36'
south at 122° 7.6' east off the south end of the island of Celebes in
Buton Strait. The easternmost record is 0° 32.5' south and 126°
31.5' east, or, less accurately, at the southern end of Molucca Passage
east of Tomini Bay. The largest number of specimens (217) was
taken February 7, 1908, at 8.05 in the morning, from 25 fathoms by
an open 0000 grit-gauze net towed horizontally 9 fathoms above the
bottom of the Sulu Archipelago, near Basilan Island, at 6° 44.2'
north and 121° 47' east. The other records are given in the table
following.

262 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

i§S o S3 c*

i-« F-i 00 t^ O

•ssss«§M

^>S a^o^

-s-sS&Bsi

<N M <N S »-« <N

^gaccoccoooM-o

CKAETOGJSTATHA COLLECTED BY STEAMER ALBATEOSS.

263

SAGITTA PLANKTONIS Steinhaus.

Sagitta planktonis STEINHAUS (1896), p. 39. — RITTER-ZAHONY (1911), p. 29. —

MICHAEL, (1911), p. 44.
Sagitta zetesios FOWLER (1905), p. 67; (1906), p. 22.

Eighty-seven specimens were obtained, but unfortunately all except
one were preserved in alcohol, with the result that they are so badly
distorted as to prevent certain identification. Measurements of the
single well-preserved specimen are:

Length 27 mm.

Width 8. 5 per cent of length.

Tail:

Length 24. 5 per cent of length.

To central ganglion 68. 0 per cent of length.

Ventral ganglion (length) 4. 0 per cent of length.

Posterior fin:

Length 20. 5 per cent of length .

Width 4. 5 per cent of length.

To anterior fin 4. 5 per cent of length.

Proportion in front of tail-septum 77. 0 per cent.

Anterior fin :

Length '. 23. 0 per cent of length.

Width 2. 5 per cent of length.

To ventral ganglion 0. 0 per cent of length.

Collarette:

Length 25. 0 per cent of length.

To ventral ganglion ' 0. 0 per cent of length.

Number of anterior teeth 8-7

Number of posterior teeth 17-18

Number of seizing jaws 8-8

The length, number of anterior and posterior teeth, and number of
seizing jaws of a few other individuals are:

Length in
mm.

Anterior
teeth.

Posterior
teeth.

Seizing jaws.

11.5
13
16.5
17
21
25

7-6
9-9
9-10
10-9
8-8
9-8

13-12
16-?
16-15
17-18
16-17
18-17

9-8
7-8
9-9
8-8
8-8
8-9

The number of teeth is greater than in specimens from the San
Diego region (Michael, 1911, p. 45). San Diego specimens, ranging
in length between 15 and 26 mm., have 4 to 7 anterior, and 11 to 15
posterior teeth. In the Biscayan report, however, Fowler (1905, p.
68) records a variation in number of anterior teeth from 5 to 9 and of
posterior teeth from 11 to 19 in individuals between 11 and 21 mm.
in length.

Distribution. — 8. planktonis was collected from only seven stations.
Of the 84 specimens obtained, 53 were taken from below 100 fathoms
by open nets towed horizontally at four stations for approximately

264 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

1

a s a a a a a a a

a d P. a cs os d

20 minutes at each. The 35 remaining
specimens were taken from above 15
fathoms at the three remaining stations
by 20-minute tows. These facts in-
dicate that the species is typically
mesoplanktonicin the Philippine region,
which indication is supported by the
results of many other expeditions. In
the regions covered by the Biscayan,
Siboga, and Plankton expeditions, as
well as off the California coast, the
species occurs abundantly below 100
fathoms, but is rarely found above that
depth. It is common between 500 and
1,000 fathoms, and, as Ritter-Zahony
(1911, p. 62) says: "S. planktonis ist
unter alien Arten der Tiefsee am hau-
figste/i in der Literatur erwahnt."

Genus PTEROSAGITTA Costa.

Syn. Spadella LANGERHANS (part 1).

PTEROSAGITTA DRACO (Krohn).

Plate 36, figs. 11, 12, 13.
Sagitta draco KROHN (1853), p. 273.
Pterosagitta mediterranea COSTA (1869), p. 55.
Spadella draco FOWLER (1906), p. 25. —

MICHAEL (1911), p. 54.
Pterosagitta draco RITTER-ZAHONY (1911),

p. 33.

Thirty-two specimens were obtained,
of which only one has mature ovaries.
These completely fill the body cavity
(pi. 36, fig. 13), extending from tail-
septum to neck. All other specimens
are clearly immature, and in nearly
one-half there is no trace of ovaries,
and the seminal vesicles are barely
visible (pi. 36, fig. 12). Fowler (1906,
p. 26) records the tail as 41 to 57 per
cent of total length in specimens be-
tween 6 and 9 mm. The Philippine
specimens, however, vary only between
39.5 and 44.3 per cent. Otherwise
Fowler's records agree exceptionally
well with the Philippine material.
He records 7 to 9 seizing jaws, 7 to

CHAETOGKATHA COLLECTED BY STEAMER ALBATROSS.

265

10 anterior teeth, and 11 to 16 posterior teeth; the Philippine speci-
mens show 7 to 9 seizing jaws, 6 to 10 anterior teeth, and 10 to 16
posterior teeth.

Nearly half the Philippine specimens are devoid of the collarette,
except for a narrow strip behind the head. This caused consider-
able trouble in identification until others were discovered in which
the structure was partly missing. These (pi. 36, figs. 12 and 13)
indicate that for some unknown reason the collarette has been torn
off. Immature specimens in this condition bear a striking super-
ficial resemblance to young S. jerox.

TABLE 17. — Measurements of Pterosagitta draco.1

Number.

Length in mm.

Width with colla-
rette.

Width without
collarette.

Length of tail.

sl

I

Length of ventral
ganglion.

Lateral fin.

Ovary.

Number of ante-
rior teeth.

|
ol

ji

Number of seizing
jaws.

a

i

"6.T
5.7

6.8
5

"i'e"

6.3
5.7
5.3
4.8
6.1
5.5
4.8
5.6
6.5
5.8
5.3
4.8

It

£°

43

&

1

5

1

2
3
4

7
8
9
10
11
12
13
14
15
16
17
18
19
20

7.7
7.6
7.4
7.2
7
6.9
6.9
6.7
6.7
6.6
6.6
6.3
5.8
5.8
5.6
5.4
5.4
5.3
5.1
4.9

7.8
6.9
7.1
10.7
8
7.6
6.6
6.8
7.8
8.5
7.4
7.3
7.9
7.9

S:i

7.8
6.7
6.2
7.1

43.3
44

42.8
39.5
44
40.3
43.1
41.4
40.5
40.9
42
41.3
40
42.3
41.6
42.5
40.8
41.3
41.4
44.3

66.6

66.5
65.6
59.6
66.9
65.2
66.5
65
64
62.7
65
64.8
63.6
66.7
66.5
65.5
64.2
64.5
64.9
68.5

9.1
8.7
9.1
7.8
8.5
9.2
8.1
10
9.9
10.6
9.6
9.5
9.7
6.7
8.7
9.8
9.7
10.7
11
10.7

22.8
23.4
22.4
20
23
23
22.3
23.1
21.3
21.8
19.1
22.9
21.8
18.8
16.8
20.2
20.8
22.7
20.7
21.4

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

o

24.6
24.8
25.7
47.8
21
10.7
20.8
9.5

2.3
2.7
1.9
5.9
4.5
.5
1.5
1

9-8
9-8
9-8
5-6
8-7
7-6
8-8
8-7
10-9
7-7
6-6
9-8
6-7
9-8
8-7
8-7
7-7
7-7
6-6
7-6

13-13

(?)-14
15-16
11-12
14-13
14-(?)
13-13
13-14
15-(?)
14-15
11-12
14-(?)
11-11
14-14
12-11
14-15
(?)-H
10-11
11-12
13-13

8-7
8-8
8-9
8-8
8-9
8-9
8-8
8-8
8-8
8-8
9-9
8-8
9-9
8-9
9-8
8-9
7-7
8-8
(?)-8
7-7

16.6
15.2

"ie.Y

13
13.3

"isT
...5...

........

10.4

6.8

1.1

"is""

"5""

1 All measurements made in per cent of total length of animal.

Distribution. — P. draco was obtained from only five stations, all
of which were subsurface ones. Two were mesoplanktonic, but they
only yielded four specimens. The remaining 28 were obtained from
between the surface and 25 fathoms, indicating that hi so far as the
species occurs in the Philippine region it is typical of the upper epi-
plankton. This accords with what is known of its distribution gen-
erally. Although nowhere abundant it is apparently restricted to
the upper epiplankton of tropical and subtropical regions. Says
Ritter-Zahony (1911, p. 63): "Ihre Verbreitung diirfte sich mit der
von S. enflata und 'bipunctata decken, doch ist die Art in den gemassig-
ten Zonen, soweit sie iiberhaupt noch darin vorkommt, schon seltener
als jene beiden. . . ." Its northernmost and southernmost records
of occurrence are 42° north, 56° west; and 42° south, 36° east.
Its records of capture during the Philippine expedition are given in
the table following:

59318— 19— Bull. 100 3

266

BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

* fc
«»'

op

os^rto

se-

f.!l

iilll

fifiQOQ

Genus EUKROHNIA Ritter-Zfihony.

Syn. Krohnia LANGERHANS (part).

EUKROHNIA HAMATA (MSbius).

Plate 37, figs. 14,27.

Sagitta hamata MOBIUS (1875), p. 158.

Krohnia hamata KRUMBACH (1903), p. 639.— FOW-
LER (1905), p. 74; (1906), p. 23.

Eukrohnia hamata RITTER-ZAHONY (1911), p. 39. —
MICHAEL (1911), p. 51.

This species is represented by six poorly
preserved and badly damaged specimens (Cat.
No. 17928, U.S.N.M.). The heads of all but
two are missing and in one of those it is
torn away from the body. It is impossible,
therefore, to accurately determine the length
or to count the teeth and seizing jaws in
four of the six specimens. The other two
are 16 and 16.3 mm. in length; their tails
are 28.3 and 30.2 per cent of their lengths;
the number of teeth are 21-21 and 24-25,
and the number of seizing jaws are 9-10
and 9-9.

The number of teeth (pi. 37, fig. 14) greatly
exceed that recorded by Ritter-Zahony
(1911, p. 39) for specimens taken from the
Antarctic Ocean, as well as that recorded
by me (1911, p. 52) for specimens from the
San Diego region. Although Ritter-Zahony
records a variation in number of teeth from
4 to 23, he gives 12 as the upper limit for
specimens under 18 mm. in length. Simi-
larly, in specimens from the San Diego region
between 13 and 17.5 mm. in length, I have
never found more than 13 teeth. Fowler
(1906, p. 23), however, records 22 in speci-
mens from the Siboga area that are only 13
mm. hi length. It is evident, therefore,
that the number of teeth vary according
to the region in which the species occurs.

The pouits of the seizing jaws (pi. 37, fig.
27) are curved to an unusual extent, and
the jaws are not serrated as described by
Krumbach (1903). Otherwise, however, the
structure of the jaws agree with his de-
scription.

CHAETOGNATHA COLLECTED BY STEAMER ALBATEOSS.

267

The six specimens were all obtained November 6, 1908, in the
China Sea in the vicinity of Formosa, at station D. 5320, 20° 58'
north and 120° 3' east by an open 0000 grit-gauze net towed at 3.18
p. m. in 500 fathoms for 20 minutes.

EUKROHNIA RICHARDI Germain and Joubin.

Plate 36, fig. 10; plate 37, figs. 15, 26.
Eukrohnia richardi GERMAIN and JOUBIN (1912), p. 2.

This species (pi. 36, fig. 10) is represented by five specimens, only
two of which are well enough preserved to permit certain identifi-
cation. Measurements of these two (a and 6), and, for comparison,
those taken from Germain and Joubin's drawing (c), are as follows:

a.

b.

C.

Length in mm ...

27.7

27 8

27 8

Width in per cent of length

12.9

13.3

12.2

Tail:
Length in per cent of total length

27.2

26.2

25.2

To ventral ganglion in per cent of total length

70 7

74 2

67 6

Length of ventral ganglion in per cent of total length

6.6

5.2

2.9

Lateral fin:

73 1

69 3

68 4

Width in per cent of total length ... ....

4.9

6 5

6 5

Extends bevond anterior end of ventral ganglion, in per cent
of total length
Proportion in front of tail-septum (per cent)

10.4
82.7

6.5
86.4

10.8
74.4

Ovary:

4 g

6 5

10 8

Width in per cent of total length

1.26

2.64

2 88

22 21

25-24

24

Number of seizing jaws

10-11

10-10

8

It is questionable whether this species is valid or not. It closely
resembles E. hamata, but according to Germain and Joubin (1912,
p. 5), "il s'en distingue facilement, en dehors de sa coloration verte
caracte"ristique et jusqu'a present absolument unique chez tous les
Chetognathes, par la forme tres diff e"rente de sa tfite, beaucoup plus
nettement triangulaire allong6e, par ses crochets plus e'troitement
allonges et par ses dents, au nombre de 24, alors qu'on en compte
seulement de 20 a 22 chez I' Eukrohnia liamata" Of these distinc-
tive features it is evident that differences in the number of teeth
and shape of head are of no specific value, and it seems probable
that the color, which is described (p. 2) as "d'un vert d'eau plus
fonce a la region ante"rieure et s'attenuant re'gulierement vers la
queue," is also highly variable. In the Philippine material at least,
specimens of E. hamata agree quite as well with this description as
those of E. richardi. Both, although considerably faded by action
of the f ormalin, are dark green and more so anteriorly than posteriorly.

Again, the various dimensions of the body recorded by Germain
and Joubin (p. 4) do not agree with those taken from the drawing.
The drawing measures 139 mm. in length. Assuming the recorded
length of 27 mm. to be accurate, the magnification of the drawing
is 5.15. This makes the length of tail 6.8 mm., or 25.2 per cent of

268 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

total length, but it is given as 6.5 mm., or 24 per cent of the total
length. It is stated that the ovaries are 2.25 mm. in length, or 8.3
per cent of the length of animal, but in the drawing they measure
10.8 per cent, which is equivalent to 2.92 mm. The maximum width
of body ("y compris la largeur des nageoires") is given as 2.5 mm.,
or 9.3 per cent of the length of animal, but in the drawing it measures
11.5 per cent, which is equivalent to 3.1 mm. Finally, it is stated
that the lateral fin occupies "17/27 [63 per cent] de la longeur totale
de 1' animal," that it extends 5.5 mm. anterior to the ventral ganglion
or "a environ 3 millimetres de Textre'mite' du corps," but in the
drawing it measures 68.4 per cent of the total length of animal and
extends only 10.8 per cent, or 2.92 mm., anterior to the ventral
ganglion.

Although these discrepancies are, for the most part, small, they
make it impossible to depend with certainty upon either the descrip-
tions or the drawing, and whether E. richardi is or is not synonymous
with fi. Jiamata must remain undecided until the type is more accu-
rately described. In spite of this uncertainty there are several
points that indicate its validity:

1. The seizing jaws (pi. 37, fig. 26) are more massive than those of
E. Jiamata and their points are quite dissimilar. In E. Jiamata the
points are always sickle-shaped (pi. 37, fig. 27), although they are
not usually curved so much as in the Philippine material; the top
of shaft and base of point converge upon approaching the edge of
the jaw; the point has an oval base; and the pulp-canal is central
and sparsely filled with pulp. In E. richardi, on the other hand, the
points are not sickle-shaped; the top of shaft and base of point are
parallel; the point has an irregular rather than an oval base; the
pulp-canal is irregular in outline and is displaced toward the back
of shaft; and the pulp is evenly distributed.

2. The body of E. richardi is between two and three times wider
in proportion to the length of animal than is the case with E. Jiamata.

3. Lateral fins extend to, but rarely beyond, anterior end of
ventral ganglion in E. Jiamata, while in E. richardi they extend
beyond the anterior end of ganglion by 6 to 11 per cent of the length
of animal.

4. Lateral fins in E. Tiamata with "fin-rays extending about as far
in front of the septum as the fin does behind it, but the fin continued
forwards as an expansion of the epidermis up to or to the middle of
the ventral ganglion." [Fowler (1905, p. 74).] In E. richardi the
fin, according to Germain and Joubin, is delicately rayed throughout,
the rays making an acute angle with the body as illustrated by their
drawing. This seems to be true of the Philippine specimens (pi. 36,
fig. 10), although the rays are fewer and much finer toward the
anterior end.

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS. 269

5. Lateral fins never extend more than halfway from tail-septum
to seminal vesicles in E. Jiamata, while they extend three-quarters of
the distance, according to Germain and Joubin's drawing, and quite
to the anterior end of the vesicles in the Philippine specimens.
. The Philippine specimens apparently differ from the type in two
points :

(1) Germain and Joubin state that the ventral neck muscles are
composed of longitudinal fibers, together with very fine transverse
ones. The transverse fibers are absent in the Philippine specimens.

(2) The seminal vesicles are figured and described as very small
disks lying within the anterior end of the caudal fin. In the Phil-
ippine specimens this is not the case, although the vesicles in all
specimens were very immature. Their appearance, however, sug-
gests that when mature their posterior extremities may touch the
caudal fin.

The five specimens (Cat. No. 17929, U.S.N.M.) were all obtained
at 12.07 in the afternoon, May 8, 1909, station D. 5437, off the west
coast of Luzon, 15° 45/9 north and 119° 42/8 east, by an open
0000 grit-gauze net towed for 27 minutes in 450 fathoms.

Genus KROHNITTA Ritter-ZShony.

Syn. Krohnia LANGERHANS (part).
Spadella GRASSI (part).
Krohnia STRODTMAN (part).

KROHNITTA SUBTILIS (Grassi).

Spadella subtilis GRASSI (1883), p. 23.

Krohnia subtilis STRODTMAN (1892), p. 22.— FOWLER (1905), p. 78; (1906), p. 25.
• Krohnia padfica FOWLER (1906), p. 24.
Eukrohnia subtilis MICHAEL (1911), p. 52.
Krohnitta subtilis RITTER-ZAHONY (1911), p. 44.

Only three specimens were obtained, all of which are immature.
Only one is sufficiently well preserved to permit accurate measure-
ments :

Length in mm 9.8.

Length of tail 35.9 per cent of total length.

Tail to ventral ganglion 63.5 per cent of total length.

Length of ventral ganglion 7.5 per cent of total length.

Length of fin •. . 35.1 per cent of total length .

Width of fin 6.4 per cent of total length.

Proportion of fin in front of tail-septum 32.7 per cent.

Length of ovary 8.6 per cent of total length-
Width of ovary 2.1 per cent of total length.

Number of seizing jaws 8-8.

The teeth could not be counted, but in the two other specimens,
which were about the same length, the number of teeth on the right
and left sides are 11-10 in one and 12-13 in the other specimen.
Similarly, the number of seizing jaws are 8-7 in the first specimen
and (?)-7 in the second.

270 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

Two of the specimens (Cat. No. 17931, U.S.N.M.) were obtained
between Panay and Negros at station D. 5185, 10° 5/8 north and
122° 18/5 east, on March 30, 1908, at 5.26 in the afternoon, by an
open 0000 grit-gauze net towed horizontally for 20 minutes in 550
fathoms. The third specimen (Cat. No. 17930, U.S.N.M.) was
obtained in the China Sea in the vicinity of Formosa, at station
D. 5319, 21° 31' north and 117° 53' east, on November 5, 1908, at
7.23 in the afternoon, by the same net towed for 27 minutes in 20
fathoms.

COMPARISON OF PHILIPPINE CHAETOGNATHA WITH THOSE FROM
THE SAN DIEGO REGION.

Aida (1897) describes 10 species from Misaki Harbor, Japan, of
which all except 8. regularis and 8. Jiispida ( = 8. robusta Doncaster)
are represented in the Philippine collection. Again, Doncaster
(1902) records 10 species from the Maldive Archipelago, of which all
save 8. regularis and 8. Jiispida are present in the Philippine material.
Likewise, Fowler (1906) describes 14 species from the "Siboga"
area, of which all save 8. regularis and 8. hispida have been taken
from the Philippines. Lastly, Bitter-Zahony (1910) lists 10 species
from Sharks Bay, Australia, of which all except 8. regularis and 8.
bipunctata are represented in the Philippine collection. The only
species obtained from the Philippines which are not recorded from any
of these regions are 8. pJiilippini and E. richardi, the former a new
species represented by a single individual, and the latter a rare
species represented by only five specimens. Obviously these facts
strongly point toward a uniformity in the chaetognath fauna, espe-
cially the epiplankton, over the Indo-Pacific Ocean, notwithstanding
the curious absence of 8. regularis and 8. Jiispida in the Philippine
collection.

The situation is quite otherwise when the Philippine chaetognatha
are compared with those from the San Diego region, for those species
most characteristic of the Philippines are those that are either
absent or least characteristic of the San Diego region, and the op-
posite. Thus, 8. enflata, by far the most typical and abundant
species about the Philippines, has been obtained in the San Diego
region by less than 20 out of nearly 4,000 hauls. Conversely, 8.
bipunctata is by far the most typical and abundant species in the
San Diego region, but not a single individual was obtained from the
Philippines. Again, Sagittaferox, 8. pulcJira, 8. bedoti, 8. decipiens, 8.
minima, 8. macrocephala, and Eukrohnia richardi have not been taken
from the San Diego region, although the first three are third, fourth,
and sixth in order of abundance in the Philippine region. On the
other hand, Sagitta lyra and 8. californica, in addition to 8. bipunctata,
were not taken from the Philippine region, although the former is

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS. 271

the most characteristic mesoplanktonic species in California waters.
Again, of those species common to both regions, Sagitta Jiexaptera and
S. serratodentata are second and eighth in order of abundance in the
Philippines and tenth and second in the San Diego region. Finally,
aside from S. neglecta, which is rare in the San Diego region and ob-
tained by only one haul from the Philippines, the order of abundance
of the remaining species common to both regions is as follows: S.
planktonis, P. draco, E. Tiamata, and K. subtilis in the Philippine
region; and E. hamata, K. subtilis, S. planktonis, and P. draco in the
San Diego region.

Taken in connection with what is known of the distribution of
chaetognatha throughout the world, the above comparisons show that
the Philippine species are characteristic of the Tropics and warm
water, while those of the San Diego region are, on the other hand,
more characteristic of the Arctics or sub-Arctics and cold water.
As a matter of fact there is less difference between the California
chaetognatha and those of the region about Spitzbergen than there
is between the California and Philippine faunas.

Furthermore, this sub-Arctic nature of the California chaetognatha
is not peculiar to that group. Calanus finmarchicus , the commonest
copepod of the California coast is, according to Cleve (1900, p. 47),
a "characteristic inhabitant of the Arctic regions, along the coast
banks of Greenland, Iceland, etc." Similarly, Eucalanus elongatus,
the second most typical copepod of California waters, is "noted from
60° north, 7° west in August and the Skagerak in February." [Cleve
(1900, p. 63.)] Likewise Acartia clausii, obtained in abundance off
the pier of the Scripps Institution, is typical of the North Sea " and
follows the coast of Norway to about 70° or 74° north." [Cleve (1900,
p. 42).] Again, the most prevalent ctenophore of the California
region, PleurolracMa lachei, "is found in vast swarms in the cold
water of Maine and Nova Scotia." [Esterly (1914, p. 28).] Lastly,
among the diatomaceae, CJiaetoceros criophilum is the commonest
diatom in San Diego waters, although Cleve (1900, p. 295) states
that it is a "decidedly Arctic, pelagic species." Another common
San Diego CJiaetoceros is C. debile, but Cleve (1900, p. 296) says that
it is abundant along the south coast of Iceland and at the Faroes."
Similarly with Nitzschia seriata, its "principal area of distribution
is between Scotland, Iceland, and Greenland" [Cleve (1900, p. 336)],
although it is among the common diatoms of the San Diego region.

So the list might be continued. To be sure, there are many
tropical and semitropical species occurring in California waters, but
they are not the characteristic and prevalent ones. These have their
nearest allies, not in other parts of the world at corresponding lati-
tudes, but in the Arctic and sub-Arctic regions. May this not be
attributable in part to the marked upwelling of cold bottom waters

272

BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

along the western coast of America ? To establish this would require
an extensive series of collections off the coast of Central and South
America, and comparisons of the faunas at the same latitudes on the
two sides of the Pacific. But, if it is true, it emphasizes the necessity
of recognizing this fact in fisheries investigations and demonstrates
an essential difference between the problems, economic and otherwise,
of the coastal waters of the eastern and western Pacific.

That the chaetognath faunas of the two regions are fundamentally
different is made more certain by the fact that in four of the five
Sagitta l common to both Philippine and San Diego regions, the
Philippine specimens have a greater number of both anterior and
posterior teeth. The same is true with respect to P. draco, and in
E. hamata the Philippine specimens have nearly twice as many
teeth (21 to 25) as do the San Diego specimens (10 to 13). These
differences are mentioned in the preceding pages in connection with
the account of each species, but are better revealed, perhaps, in the
following list:

Species.

Anterior teeth.

Posterior teeth.

Philippines.

San Diego.

Philippines.

San Diego.

8. enflata

6-11
4-8
8-11
6-10
6-10

4-8
3-5
6-9
4-7
4-4

9-15
12-16
13-24
12-18
10-16

7-12
8-11
13-19
11-15
8-9

S. serratodentata

S. planktonis
P. draco

In the case of P. draco the differences may mean little, owing to
the fact that only a single very immature specimen is recorded from
the San Diego region. It is interesting, however, to note that it was
7 millimeters in length, whereas 15 of the 20 from the Philippine
region recorded in Table 17 are smaller and quite as immature, the
smallest being less than 5 millimeters in length, although it has
6 to 7 anterior teeth and 13 posterior teeth.

To demonstrate that the differences in number of teeth given for
the four species of Sagitta are significant, from 10 to 30 or more
individuals of each species were selected at random from the two
collections, the number of teeth counted, and the mean number and
corresponding probable errors computed. The results are entered in
Table 19:

TABLE 19. — Comparison of mean number of teeth in specimens from the Philippines and
from the San Diego region.

Species.

Anterior teeth.

Posterior teeth.

Philippines
(P).

San Diego

(S).

Difference
(P-S).

Philippines
(P).

San Diego

(S).

Difference
(P-S).

8. enflata

8. 29 ±0.256
5. 61 ±0.160
9.32±0.133
8.36±0.200

6.27±0.035
3. 80±0. 243
7. 22±0. 114
5. 94 ±0.335

2. 02 ±0.258
1.81 ±0.291
2. 10±0. 175
2.42±0.390

13.45±0.241
13. 75± 0.184
18. 24 ±0.536
16. 15 ±0. 145

10. 18± 0.133
8. 96 ±0.135
15.44±0.203
12.60±0.218

3. 27 ±0.275
4. 79 ±0.22?
2. 80±0. 573
3. 55 ±0. 262

S. ner/lecta
S. serratodentata
S. planktonis.

hexaptera is not considered owing to loss of teeth. See p. 245.

CHAETOGNATHA COLLECTED BY STEAMER ALBATBOSS.

273

Table 19 shows (1) that in every case the mean number of both
anterior and posterior teeth in Philippine specimens exceeds that in
San Diego specimens, and (2) that the magnitude of the excess is
between 5 and 20 times the corresponding probable error. That this
excess is not merely an expression of the larger size of the Philippine
specimens is evident, for the counts were made on specimens of
Philippine Sagitta enflata between 10 and 21 mm. in length and on
San Diego specimens between 10 and 25 mm.; on Philippine S.
neglecta between 6 and 8 mm., and on San Diego specimens between
8 and 13 mm.; on Philippine S. serratodentata between 7 and 11 mm.,
and on San Diego specimens between 10 and 17 mm.; and on Philip-
pine S. planktonis between 13 and 27 mm., and on San Diego speci-
mens between 17 and 26 mm. Obviously, some differential influence
is at work in the two regions causing an excess of teeth in the Philip-
pine fauna, or a deficiency in the San Diego fauna.

Unfortunately, a similar comparison of Philippine chaetognatha
with those from other regions of the Pacific is impossible, owing to
the fact that no one except Fowler (1906) has published a series of
tooth counts, and he has not kept the individual counts distinct.
The range of variation, however, in the Siboga material is much the
same as that in Philippine specimens. This is pointed out in the
foregoing pages for every species common to the two regions, but
these data are brought together and amplified in Table 20 :

TABLE 20. — Comparison of number of anterior and posterior teeth in Philippine species
and those from the Siboga region.

SAGITTA ENFLATA.

L^U,

specimens
In mm.

Anterior teeth.

Posterior teeth.

Philip-
pines.

Siboga.

Philip-
pines.

Siboga.

10-15
15-20
20-25
25-30

6- 7
7-9
7-11

8

7- 9
8-9
8-10
7-10

9-12
13-15
14-15
14

9-14
12-17
12-16
14-17

SAGITTA NEGLECTA.

6.5 4-6

4- 5

12-14

9-10

7 5-8

4- 6

12-16

9-12

7.5

5- 6

4- 5

14-15

10-13

8

5-6

4- 6

14-15

9-14

SAGITTA SERRATODENTATA.

7- 8

9

5-9

13-15

9-16

8- 9

8- 9

6-9

14-18

13-18

9-10

8-9

6-9

' 16-19

13-19

10-11

8-11

8 9

18-24

15-19

274 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

TABLE 20. — Comparison of number of anterior and posterior teeth in Philippine species
and those from the Siboga region — Continued.

SAGITTA PLANKTONIS.

Length of
specimens
in mm.

Anterior teeth.

Posterior teeth.

Philip-
pines.

Siboga.

Philip-
pines.

Siboga.

11-13
13-15
15-17
17-19
19-21
21-23
23-25
25-27

7- 9
9
9-10
9-10
8
8
8- 9
7- 9

5- 8
5- 9
8- 9
7- 9
7-11
8-11
8-10
8- 9

12-10
16
15-18
17-18
16-17
16-17
17-18
17-18

13-16
14-18
17-18
16-18
16-20
17-20
18
18-19

SAGITTA PULCHRA.

10-15

15-20
20-25

5- 8
6-9

6- 8

6-10
6-10
7-10

9-12
11-13
10-13

10-14
10-15
12-15

SAGITTA DECIPIENS.

9.0
11
12
12.5

9-11
10-11
9

8-9

8
7
8
8- 9

19-21
22

20-21
19-20

16
16
15-17
15-18

SAGITTA BEDOT1.

10-12
12-14
14-16

8-10
8- 9
8-10

9-11
9-13
9-10

20-23
21-25
22-28

18-27
20-32
21-29

SAGITTA FEROX.

10-12
12-14
14-16

5- 7
7- 9
5- 9

4- 8

7- 9
6- 9

10-12
12-15
10-14

9-13
10-14
10-14

PTEROSAGITTA DRACO.

6.0

7
7.5

7- 9
5-10
8- 9

8
7-10
8- 9

11-14
11-15
13-16

12
11-15
12-16

Inspection of this table reveals a pronounced similarity in number of
both anterior and posterior teeth between Philippine and Siboga speci-
mens oiSagitta enflata, S. planktonis, S. pulchra, S. bedoti, S.ferox, and
Pterosagitta draco. In S. neglecta, S. serratodentata, and 8. decipiens
specimens from the two regions agree in number of anterior teeth,
but those from the Philippines have a greater number of posterior
teeth. Even in these instances the differences are slight and prob-
ably insignificant except for 8. decipiens. In this species there
seems to be no doubt that the Philippine specimens have more
posterior teeth than Siboga specimens of the same length, although,
as pointed out on page 254, where the length of animal was neglected,
Fowler's records show a range of 13 to 23 posterior teeth as against
that of 19 to 22 for Philippine specimens.

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS. 275

On the whole there is close agreement in number of teeth between
specimens of species common to the Philippines and the Siboga
region, while the same species are represented in the San Diego
region, if at all, by specimens having markedly fewer teeth. In
the face of this fact it is evident that, as formerly (1911, p. 68)
stated, "variation in number of both anterior and posterioi teeth
in many species is not referable to specific differences, but probably
to some distribution factor." When it is recalled that a subnormal
ocean temperature characterizes the region adjacent to the western
coast of America, due to pronounced upwelling of bottom water,
and that the chaetognath fauna off southern and Lower California
is representative of more northern latitudes, it suggests that one of
these distribution factors is temperature. I believe the small num-
ber of teeth in San Diego specimens is an expression of the slower
rate of metabolism due to a lower ocean temperature. This is not a
new suggestion, but it is one that merits thorough investigation.
Fowler (1906, p. 29), after stating that specimens of Siboga Sagitta
serratodentata have nearly twice as many posterior teeth as speci-
mens of the same length from the Bay o^f Biscay, says: "It is possible
that this may be correlated with the respective temperatures at
which the specimens live, but a long series of similar observations
from different latitudes would be necessary before this could be
regarded as even probable."

LITERATURE CITED.

AlDA, T.

1897. The Chaetognatha of Misaki Harbor. Annot. Zool. Japon., vol. 1, pp.

79-81, pi. 4.
BALDASSERONI, V.

1915. Chetognati. Raccolte Planktoniche fatte dalla R. N. "Ligura" nel

viaggio di circonnavigazione del 1903-05, vol. 2, pp. 85-117, pis. 6-7.
BERANECK, E.

1895. Les Che"tognathes de la Bale d'Amboine. Rev. Suiese Zool., vol. 3, pp.

137-159, pi. 4.
CLEVE, P. T. ; r

1900. The seasonal distribution of Atlantic plankton organisms. Goteborg.
Vetensk. Vitterhets-Samhull. Handl. F., vol. 4, Heft 3, No. 3, 368 pp.
CONANT, F. S.

1895. Description of two new chaetognaths. J. Hopkins Univ., Circ., vol. 14,

pp. 77-78, pi. 1.
COSTA, A.

1869. Di un nuovo genere di Chetognati. Ann. Mus. Zool. Univ. Napoli, vol. 5,

pp. 54-57.
DONCASTER, L.

1902. Chaetognatha, with a note on the variation and distribution of the group.
Fauna and Geogr. Maldive-Laccadive Archip., vol. 1, pp. 209-218,
pi. 13, figs. 39-40 in text.
ESTERLY, C. O.

1914. A study of the occurrence and manner of distribution of the ctenophora of
the San Diego region. Univ. Calif. Publ. Zool., vol. 13, pp. 21-38.

276 BULLETIN 100, UNITED STATES NATIONAL MUSEUM.

FOWLER, G. H.

1905. Biscayan plankton collected during a cruise of H. M. S. Research, 1900.

Part 3. — The Chaetognatha. Trans. Linn. Soc. London, ser. 2, vol. 10,
pp. 55-87, pis. 4-7.

1906. The Chaetognatha of the Siboga expedition, with a discussion of the

synonymy and distribution of the group. Siboga Exped. Monogr.
No. 21, 86 pp., 3 pis., 6 maps.
GERMAIN, L., and JOUBIN, L.

1912. Note sur quelques Che'tognathes nouveaux des croisieres de S. A. S. le

Prince de Monaco. Bull. Inst. Oc&inogr., No. 228, 14 pp., 15 figs, in text.
GRASSI, B.

1881. Intorno ai Chetognati. Atti Inst. Lombard, ser. 2, vol. 14, pp. 193-213.
1883. I Chetognati. Fauna u. Flora Golfe Neapel, Monogr. No. 5, 126 pp., 13 pis.
KROHN, A.

1853. Nachtragliche Bemerkungen iiber den Bau der Gattung Sagitta, nebst der
Beschreibung einiger neunen Arten. Arch. Naturgesch., vol. 19, No. 1,
pp. 266-277.
KRUMBACH, T.

1903. Ueber die Greifhaken der Chatognathen. Zool. Jahrb. Abt. System.

vol. 18, pp. 579-646, figs. A-U in text.
MICHAEL, E. L.

1911. Classification and Vertical Distribution of the Chaetognatha of the San
Diego region, including redescriptions of some doubtful species of the
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1913. Sagitta californica, n. sp. from the San Diego region, including remarks on

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1916. Dependence of Marine Biology upon Hydrography and necessity of quanti-
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n. F., Abt. Kiel, vol. 2, pp. 158-159.
D'ORBIGNY, A.

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fig.l.

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No. 10, 47 pp., 2 pis.

CHAETOGNATHA COLLECTED BY STEAMER ALBATROSS. 277

EXPLANATION OF PLATES.

[All figures drawn with camera luclda.]
PLATE 34.

FIG. 1. Sagitta philippini, new species. X 18.

. 2. Anterior teeth and few of posterior teeth of S. philippini. X 250.

3. Vestibular ridge of S. philippini. X 250.

4. Seizing jaws of S. philippini. X 800.

PLATE 35.

FIG. 5. Sagitta pukhra Doncaster. X 8.

6. Sagitta bedoti Be>aneck. X 8.

7. Sagitta ferox Doncaster. X 8.

8. Sagitta dccipiens Fowler. X 18.

9. Sagitta neglecta Aida. X 18.

PLATE 36.

FIG. 10. Eukrohnia richardi Germain and Joubin. X 6.

11. Pterosagitta draco (Krohn). X 25.

12. Pterosagitta draco with collarette partly torn away and with no vestige of

ovary or seminal vesicle. X 25.

13. Pterosagitta draco with fully mature ovaries and with collarette almost

entirely missing. X 25.

PLATE 37.

FIG. 14. Teeth of Eukrohnia hamata (Mobius). X 100.

15. Teeth of Eukrohnia richardi Germain and Joubin. X 100.

16. Vestibular ridge of Sagitta minima Grassi. X 400.

17. Seizing jaw of Sagitta minima. X 800.

18. Portion of vestibular ridge and posterior teeth of Sagitta dccipiens Fowler.

X 400.

19. Vestibular ridge of Sagitta pukhra Doncaster. X 400.

20. Vestibular ridge of Sagitta bedoti Be"raneck. X 400.

21. Vestibular ridge of Sagitta ferox Doncaster. X 400.

22. Seizing jaw of Sagitta decipiens Fowler. X 800.

23. Seizing jaw of Sagitta pukhra Doncaster. X 800.

24. Seizing jaw of Sagitta bedoti Be>aneck. X 800.

25. Seizing jaw of Sagitta ferox Doncaster. X 800.

26. Seizing jaw of Eukrohnia richardi Germain and Joubin. X 800.

27. Seizing jaw of Eukrohnia hamata (Mobius). X 800.

PLATE 38.

FIG. 28. Posterior extremity of a small mature Sagitta enflata Grassi. X 25.

29. Posterior extremity of a mature Sagitta minima Grassi. X 25.

30. Ventral view of anterior extremity of Sagitta bedoti Be"raneck. X 50.

U. S. NATIONAL MUSEUM

BULLETIN ICO PL. 34

CHAETOGNATHA COLLECTED IN PHILIPPINE ISLANDS.

FOR EXPLANATION OF PLATE SEE PAQE 277.

U. S. NATIONAL MUSEUM

BULLETIN 100 PL. 35

CHAETOGNATHA COLLECTED IN PHILIPPINE WATERS.

U. S. NATIONAL MUSEUM

BULLETIN 100 PL. 36

S

CHAETOGNATHA COLLECTED IN PHILIPPINE WATERS.

U. S. NATIONAL MUSEUM

BULLETIN 100 PL. 37

23 24 25

CHAETOGNATHA COLLECTED IN PHILIPPINE WATERS.

U. S. NATIONAL MUSEUM

BULLETIN 100 PL.

•li.

CHAETOGNATHA COLLECTED IN PHILIPPINE WATERS.

INDEX.

Page.

bedotil (Sagitta), distribution of 257

measurements of 257

Philippine records of occur-
rence 258

redescription of 255

chaetognatha, comparison of Philippine and

San Diego faunas 236, 270

distribution relative to fishery

problems . 237, 272

distribution relative to up-
welling water 271,275

key to genera of 238

significance of variability in

number of teeth 272

species collected 235

validity of genera 237

decipiens (Sagitta), distribution of 255

measurements of 255

Philippine records of oc-
currence 256

redescription of 254

resemblance to S. phil-

ippini 241

variability in number of

teeth 254

distribution of E ukrohnia hamata 267

Krohnitta subtilis 270

Pterosagitta draco 265

Sagitta bedoti... 257

S.decipiens 255

ferox.

neglecta

planktonis

pulchra

serratodentata

draco (Pterosagitta), distribution of

measurements of

Philippine records of oc-

rence

variability in number of

teeth

enflata (Sagitta), distribution of

measurements of

peculiarities in maturation

of

Philippine records of occur-
rence

variability in number of

teeth

Eukrohnia, key to species of

validity of

ferox (Sagitta), distribution of 260

measurements of 260

Philippine records of occur-
rence 262

redescription of 259

resemblance to S. robusta 259

genera, key to 238

validity of 237

hamata (Eukrohnia), distribution of 267

variability in number

of teeth 266

hexaptera (Sagitta), distribution of 246

loss of teeth 245

measurements of 245

Philippine records of oc- •

currence 247

Heterokrohnia (validity of) 237

Keys, discussion of 237

to genera 238

species of Eukrohnia 240

Sagitta 238

Spadella 239

Krohnitella (validity of) 237

Krohnitta (validity of) 237

macrocephala (Sagitta) 250

measurements of Eukrohnia richardi 267

Krohnitta subtilis 269

Pterosagitta draco 265

Sagitta bedoti 257

S.decipiens 255

enflata 243

ferox 260

hexaptera 245

neglecta 258

pulchra 252

serratodentata 249

minima (Sagitta), redescription of 248

neglecta ( Sagitta), distribution of 258

measurements of 258

variability in number of

teeth 258

philippini (Sagitta), description of 240

resemblance to S. decip-

iens 241

validity of 242

planktonis (Sagitta), distribution of 263

Philippine records of oc-
currence 264

variability in number of

teeth 263

Pseudosagitta (validity of) 237

Pterosagitta (validity of) 237

m

IV

INDEX.

Page.

pulchra (Sagitta), distribution of 252

Philippine records of oc-
currence 264

variability in number of

teeth 263

richardi (Eukrohnia), measurements of 267

validityof 267

Sagitta, key to species of 238

species collected 235

validityof 237

serratodentata (Sagitta), distribution of 250

measurements of . . . 249
Philippine records

of occurrence 250

variability in num-
ber of teeth 249

Page.

Spadella, key to species of 239

validityof 237

subtilis ( Krohnitta), distribution of 270

measurements of 269

teeth (variability in number of), Eukrohnia

hamata... 266
Pteros agit-

ta draco.. 264
Sagitta de-

cipiens . . . 254

S. enflata. . . 242

neglecta . 258
plankto-

nis 263

serrato-
dentata 249
Signifi-
cance of 272

o

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