652 APPENDIX. 



In these shells sometimes the left and at other times the right 

 valve is the flatter, and furnished with the dilated ventral edge. 



Vol. ii. p. 548. Genus YOLDIA. 



Sub-gen. pobtlandia, Morch. 



Shell trapeziform, truncated posteriorly; surface of valves 

 concentrically striated or grooved. Y. glacialis and thracicqformis 

 are examples. 



Genus CHONDROSTACHYS, Macdonald. 



(FaUl. CLAVELLINID.E.) 



Individuals attached by peduncles to the upper or free part 

 of a long, upright, cylindrical stem. Body oblong, attached by 

 the peduncles horizontally ; test smooth, transparent ; branchial 

 orifice on the upper side, anal nearly terminal, both orifices four- 

 lobed. 



Ex. C. Macdonaldi, H. and A. Adams, pi. 138, fig. 16. 

 Individual, C. Macdonaldi, fig. 10, a. 



For this beautiful addition to the Tunicata we are indebted to 

 Mr. Macdonald, Assistant- Surgeon of H. M.S. "Herald," who 

 states that it was taken in a trawl from a depth of 10 12 

 fathoms, while cruising in Bass's Straits. The Individual animals 

 measured each about half an inch in length. 



