62 PACIFIC SCIENCE, Vol. XVIII, January 1964 
FIG. 3. Larvae and metamorphosis of Tedania gurjanovae Koltun. a, Sketch of a living embryo obliquely 
joined to parental mesenchyme, X 32. It is nearly ready to detach as a parenchymula larva, b, Sketch of a 
natatory parenchymula, lateral view, X 46. Note the parental (?) style and onychaete piercing the larva. 
c, Sketch of a parenchymula showing a slightly invaginated posterior pole, lateral view, X 16. d, Sketch show- 
ing from above a spherical mass of mesenchymal cells (pattern) resulting from fixation of a larva to a glass 
substratum for about 30 min, X 14. e, Sketch made from above the same larva after a fixation period of 3 
hr, X 18. Mesenchymal cells occupy the cortical region (pattern) and are encompassed by a transparent band 
of syncytium-like protoplasm. 
disc measured 1065 fx in diameter and consisted 
of an internal subspherical light-yellow mass 
800 jx in diameter surrounded by a transparent 
band of protoplasm containing no observable 
cell boundaries (Fig. j>e) . The rate of develop- 
ment in Tedania gurjanovae during the early 
stages of metamorphosis seems to be consider- 
ably more rapid than that described for Lis- 
sodendoryx similis (Ali, 1956). The length of 
time necessary for Tedania gurjanovae to reach 
histological maturity was not determined in the 
present study. Wilson (1935:295) reported that 
the formation of choanocyte chambers and canals 
in some cultures of Mycale syrinx occurred 
within 3 to 4 days after discharge of the larvae 
from the parent, and Levi (1956:81) noted 
that the histogenesis of Halisarca dujardini into 
a functional rhagon took about 2 days after 
larval fixation. 
At 1 day of age the juvenile encrustation 
revealed several small styles that were irregularly 
scattered in the mesenchyme. These may still 
have been the embryonic acanthostyles, but 
with the 112.5 X magnification of a dissecting 
microscope echinations were not apparent. At 
7 days of age the styles were showing some 
evidence of orientation perpendicular to the 
substratum. After 13 days most of the styles, 
especially in the center of the disc, were oriented 
perpendicular to the substratum. Hastate tor- 
notes were observed for the first time. A very 
thin dermal membrane with scattered mesen- 
chymal cells constituted the sponge surface. 
The endosome was translucent and archeocytes 
were concentrated at the sponge base and around 
perpendicular megascleres. The sponge had al- 
most doubled in thickness since the seventh 
day of attachment. No oscules were observed. 
At 19 days of age the colonies were almost 
unchanged except for increased thickness. One 
specimen had formed a fistule about 1.5 mm 
high. 
The colonies were last observed on 28 August 
1959 (at an age of 33 days). They had remained 
relatively minute. The largest two sponges meas- 
ured roughly 1.5 mm by 0.75 mm and 2.0 mm 
by 0.7 5 mm in diameter. Their thickness did not 
exceed 2 mm. None of the specimens showed 
evidence of oscule formation. Perhaps in culture 
these sponges remained in a diminutive condi- 
tion because their environmental conditions 
present in the laboratory differed from their 
natural deeper water habitat. 
TAXONOMIC DISCUSSION 
The holotype of Tedania gurjanovae Koltun 
is specimen No. 2974, Zoological Institut, Akad- 
emia Nauk, Leningrad, USSR. The habitat, 
habitus, and natural color of this species as 
reported by Koltun (1958:65) closely resemble 
that of local San Juan representatives. The 
spicule morphology and size are also very simi- 
lar to local forms except that the onychaetes are 
longer and more rugose in the Russian specimen. 
The endosomal anatomy is too briefly described 
to make a useful comparison. Koltun (1959: 
156) states: "The main skeleton is in appear- 
ance like an irregular net of organized bundles 
of spines.” 
