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Vol. 6; Supplement
THE VELIGER
Excretory Products of Tegula funebralis and Tegula brunnea
(Mollusca : Gastropoda)
YOLANDA I. LEONARD
Hopkins Marine Station of Stanford University,
Pacific Grove, California
(1 Table)
kidney was used since it could be more readily dissected
INTRODUCTION
free of other tissue.
QUESTIONS CONCERNING the excretory products of Tegula
All four tissues from each group of ten snails were
funebralis (A. ADAMS, 1854) arose when some rather
removed, blotted on a piece of filter paper, and weighed
casual qualitative tests were performed on the kidneys of
on a Mettler balance. A tungstic acid filtrate prepared
the snail. The right kidney appeared to contain a high
by Haden’s modification of Folin’s method (TODD, SAN
concentration of uric acid while the left kidney had none.
FORD & STILWELL, 1948, p. 352) was used to remove pro¬
This is a quantitative study of the excretory products of
tein from a tissue homogenate. The four filtrates from
this snail and the related species, T. brunnea (PHILIPPI,
the tissues of each group were stored between tests in a
1848).
freezer.
In order to interpret the results of the tests for excretory
METHODS
products, it was necessary to determine the total non¬
protein nitrogen in the various tissues. This was done by
The snails, both Tegula funebralis and Tegula brunnea,
used in these experiments were taken from the same area
the method of Folin and Wu (TODD, SANFORD & STIL
WELL, 1948, pp. 353-354) which was modified by de
near the Hopkins Marine Station in Pacific Grove, Cali¬
creasing all the constituents in proportion so that the
fornia. They were collected at low tide; all except two
final volume after the addition of Nessler’s solution would
groups were immediately killed and the tissues to be
be 10 ml.
investigated were prepared as protein-free filtrates. Two
Ammonia was determined by adding 1 ml of Nessler's
groups were kept in a tank in the laboratory for a week
solution to a solution of 1 ml of protein-free filtrate
before they were examined; they were not fed during this
and 8 ml. of distilled water. Urea was determined by the
period. The Tégula funebralis used were approximately
2- 2.5 cm. in diameter. The Tegula brunnea were slightly
modified method of Hawk-Andes (LEVINSON & MACFATE.
1952, pp. 370-371) ; the volume of all the reagents was
smaller, 1.8 - 2.0 cm. in diameter. It was necessary to
reduced proportionally to give a final volume after Ness¬
use large snails in order to obtain samples free of other
lerization of 10 ml. Twelve drops of a five per cent urease
contaminating tissues. A few Tegula montereyi (KIENER,
solution made from Arlington tablets and purified with
1850), 2.5 - 3.0 cm. in diameter, were used; these came
permutit powder were used. Benedict's method for the
from kelp beds forty feet under surface.
quantitative determination of uric acid (TODD, SANFORL
The tissues examined were the ctenidium, digestive
& STILWELL, 1948, pp. 361-362) was used without modi¬
gland, and the two kidneys. The latter (which could be
fication.
more accurately called coelomoducts) are very different
morphologically. The left kidney is known as the papillary
RESULTS
sac because of the many villi on its internal surface. Each
villus has a hemocoelic space in its center. The right
URIC ACID was found in significant quantities in the right
kidney has two lobes; the anterior one runs parallel to the
kidneys of both Tegula funebralis and Tegula brunnea,
left kidney, and the posterior one is behind the pericardial
but no trace of this compound was found in the left kid
cavity. The left kidney is white; in both Tegula funebrali,
neys of these snails. In Tegula montereyi there was no
and Tegula brunnea the right kidney is green in males
detectable uric acid present in any of the tissues tested.
and yellow in females. The posterior lobe of the right
Slight traces of free ammonia were found in the digestive
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Vol. 6; Supplement
THE VELIGER
Table 1
Uric acid N
Group Tissue
Non-protein N
Uric acid
Non-protein N X 10
mg/gwet wt
mg/g wet wt.
Tegula funebralis
Right kidney
11.8
Left kidney
0.907
Digestive gland
1.55
0.796
Ctenidium
1.55
1.89
Right kidney
40.7
Left kidney
1.66
2.81
Digestive gland
1.70
Ctenidium
Right kidney
1.36
24.4
Left kidney
Digestive gland
1.00
Ctenidium
1.45
Tegula brunnea
Right kidney
6.86
22
Left kidney
1.79
Digestive gland
2.15
Ctenidium
1.73
Right kidney
5.03
34.8
Left kidney
3.08
Digestive gland
2.66
Ctenidium
2.98
Right kidney
4.48
76.6
Left kidney
1.80
Digestive gland
3.06
Ctenidium
maintained in the laboratory for one week without added food.
gland of both Tegula funebralis and Tegula brunnea.
necessary to convert their wastes into uric acid. Tegula
Thère was no detectable urea in any of the tissues exam-
funebralis and T. brunnea, which both live in the inter-
ined. These results are presented in Table I.
tidal zone, are exposed to the air a good deal of the time
and so tend to convert their wastes into the non-toxic and
DISCUSSION
conveniently stored uric acid.
A comparison of the uric acid production of Tegula
The left kidney does not appear to have any excretory
funebralis and T. brunnea with that of T. montereyi
function and perhaps serves as an organ of reabsorption
seems to support Needham’s theory concerning the adapt-
as does the left kidney of Haliotis (HARRISON, 1961)
ive significance of uric acid formation (NEEDHAM, 1935)
Reabsorption would enable the animal to conserve many
Since T. montereyi are constantly in the water, any am¬
valuable nutrients that would otherwise be lost in the
monia formed can be continuously diffused into the sea,
urine. This function of the left kidney seems quite prob-
and so there is no need for them to expend the extra energy
able when one considers both the increase in surface area
Vol. 6; Supplement
Page 30
THE VELIGER
LITERATURE CITED
provided by the papillae and the highly vascularized
nature of these papillae.
HARRISON, F M.
1961.
Some excretory processes in the abalone Haliotis ruf¬
SUMMARY
escens.
Journ. Exp. Biol. 39 179-192
LEVINSON & MACFATE
1. Tests were performed on the snails, Tegula funebralis
1951. Clinical laboratory diagnosis.
4th ed.; pp. 1 - 1146.
and T. brunnea, to determine the nature and quantity of
Lea & Febiger, Philadelphia
their excretory products and the organs of excretion.
NEEDHAM, J.
2. Standard colorimetric assays were used on homo-
1935.
Problems of nitrogen catabolism in invertebrates. II.
genates prepared from the ctenidium, digestive gland,
Correlations between uricotelic metabolism and habitat in the
right and left kidneys. Total non-protein nitrogen, ammo¬
phylum Mollusca. Biochem. Journ. 29: 238-251
nia, urea, and uric acid were determined.
PICKEN, L. E. R.
3. Uric acid was observed to be the major excretory
1937.
The mechanism of urine formation in invertebrates. II.
product of these snails. It accounted for 11.8% to 76.6%
The excretory mechanism of certain Mollusca. Journ. Exp.
of the total non-protein nitrogen in the right kidneys, the
Biol. 14: 20 -34
only organs where this waste product was detectable.
TODD, SANFORD & STILWELL
Only slight traces of ammonia were found in the digestive
1948.
Clinical diagnosis by laboratory methods.
11th ed.
gland, and no urea was present in the tissues tested.
W. B. Saunders Co.; i-xi + 954 pp.
The Distribution and Movement of Tegula funebralis
in the Intertidal Region of Monterey Bay, California
(Mollusca: Gastropoda)
WILLIAM M. WARA
AND
BENJAMIN B. WRIGHT
Hopkins Marine Station of Stanford University,
Pacific Grove, California
(9 Text figures)
tigated Tegula funebralis intertidal distribution and move¬
INTRODUCTION
ment patterns in relation to certain biological and physical
Tegula funebralis (A. ADAMS, 1854) is very common
environmental factors. Before investigating movement pat-
along the west coast of California, although little work
terns, we wanted an accurate, correlatable distribution
has been done on its intertidal distribution. Hewatt (1934
analysis for several areas along Mussel Point, Pacific
describes its distribution as between the plus one and plus
Grove, California. To do this, we collected information
five foot level above mean lower low water. Ricketts and
pertaining to numbers and size classes of this snail along
Calvin (1962, pp. 352-355) put the population center at
with environmental data of the areas, such as vertical level
the three foot tide level. Neither reference describes the
of collection, algal covering, area configuration, substra¬
distribution extent along the intertidal region. We inves-
tum, and wave and current action. Factors that seem to