314 ASAJIRO OKA AND ARTHUR WILLEY. 
the material was obtained (there being no male genital organ 
in any of the colonies examined), and partly owing to the fact 
that while the specimens which reached Europe were in a suffi- 
ciently good condition to establish the systematic position of 
the new genus, yet they were not suitable for a very minute 
examination, especially with regard to the details of budding. 
In spite of these gaps, the most serious of which is the failure 
to observe the testis and vas deferens, the general appearance 
of the colony is so singular and characteristic, and the canal 
system so interesting, that we thought it worth while to send 
in this account. 
1. Manner of Growth and Outer Form. 
On Pl. XVITis given a reproduction of a coloured drawing of 
a living colony according to the natural size, which was executed 
at the behest of one of us by a Japanese artist. 
The portrait is singularly striking and accurate. The colour 
is a brilliant red, and the surface of the colony is smooth and 
glistening. 
At the tips of the round knoll-like lobes, which are a very 
characteristic feature of the genus, are seen the small but dis- 
tinct excurrent orifices. The lips of the pores are slightly 
raised above the level of the surrounding surface. The in- 
current orifices are, of course, the mouths of the Ascidiozooids, 
but they are too small to be seen with the naked eye on a 
living colony, which, indeed, is not transparent. 
The shape of a colony in the transverse direction is shown 
in fig. 2 on P]. XVIII. From this figure we note the unusual 
circumstance that the base or surface of attachment is con- 
siderably narrower than the free portion. 
According to the observations of one of us in Japan, the 
direction of the length of a colony is always parallel to the 
coast-line ; and further, colonies growing end to end frequently 
undergo concrescence, and in this way produce a compound 
aggregation which often attains to a great length, namely, 
two or three feet. 
This Didemnid presents a great contrast to most if not all 
