APPENDIX. 



DURING the progress of this work through the press, we have 

 been enabled to submit many of the animals referred to in 

 its pages to a careful re-examination, which has in some few 

 instances shown that our original impressions were partially 

 incorrect, and in others has caused us to modify our opinions 

 to a greater or less extent. The results of such observations 

 as were made too late to be incorporated in the body of the 

 work, are contained in the following Appendix. 



SCROBICULARIA PIPERATA. (P. 138.) 



Exmouth, July 1854. 



As my original notes upon this animal were but scanty, I 

 have gladly embraced an opportunity of making a fresh ex- 

 amination of its structure, particularly as it presents a very 

 unusual configuration of the branchiae and palpi. 



I find that these organs are of the palest brown, with a 

 slight red cast. The palpi are regularly triangular, pointed, 

 enormously large as regards length and breadth, compara- 

 tively smooth without, and strongly striated within. There 

 is only a single branchia on each side the body, of a broad 

 triangular shape, very thick, fixed by the longest side to the 

 posterior dorsal range, with the angular point vertical to the 

 ventral line ; it is divided diagonally, by a subcentral narrow 

 groove, into two subtriangular portions, whereof the one 

 nearest the dorsal slope is usually the least. Instead of one 

 part folding on the other, as in the regular two-leaved bran- 

 chiae, it is thrown back and pinned to the posterior dorsal 

 slope, forming one moderate branchial plate, certainly not much 



