62 THE AUSTRALIAN MUSEUM. 



Body not longer than broad ... ... C. Quoyi. 



Body longer than broad ... ... ... 10 



, r Ascidiozooids not less than 5 mrn. long ... 11 



| Ascidiozooids less than 2 mm. long ... C. elongata. 



,, J Colour dark blue all over C. cyanea. 



{ Colour not blue (grey in spirit) C. claviformis. 



There are, of course, many other differences between the species 

 The characters in the above table merely give an indication of which 

 species to turn to. 



I shall now describe the four new species of the Museum collection. 



Colella plicata, Herdm.,* PI. Dis. II., figs. 115. 

 ? = Aplidium ccrebriforme, Q. & G. 



External appearance. The colony consists of a peduncle, usually 

 short and wide, and a vertically flattened, expanded and greatly folded 

 or convoluted body. The peduncle is of a very pale yellowish grey, and 

 quite smooth. The lower part is columnar, while the upper part is 

 flattened and fan-like, and appears to be formed by branches from the 

 lower part which, in most cases, are not completely separated, but are 

 united by a thin membrane. The expanded body, or upper part of the 

 colony in which the Ascidiozooids are borne, is a flattened band or 

 ribbon-like structure, plicated or folded upon itself, and continuous from 

 branch to branch in those cases where the peduncle sub-divides. The 

 colour of the body is very pale yellow, almost white, and considerably 

 lighter than that of the peduncle. The following measui-ements are taken 

 from a medium-sized colony: Length of peduncle 3'7 cm., diameter of 

 peduncle 1*0 cm.; length (vertically) of body proper 1-0 cm., breadth 

 (horizontal) of body proper 6 cm. (following all the plications 26 cm.), 

 thickness (laterally) of body O5 cm. 



The Ascidiozooids are placed in vertical rows, about 6 in each, in the 

 body, two rows being always placed close together, and separated from 

 the neighbouring double rows by ridges of test. The Ascidiozooids in 

 each pair of adjacent rows are placed alternately so as to pack close 

 together. The rows are slightly divergent so as to produce a fan- shaped 

 figure, and in each row the Ascidiozooids at the base are very young, 

 while those towards the free edge of the body are large and old. The 

 vascular appendages from the Ascidiozooids can be seen running down- 

 wards, and converging for some distance through the upper part of the 



* See Revision, p. 611. 



