369 



SUPPLEMENTARY NOTES ON THE 

 ACEPIIALA. 



During tlie publication of our account of the British species of 

 this class of Mollusks, some new matter of much interest has come 

 to hand, and descriptions of several new tunicated forms made 

 public. Instead of reserving them for the general appendix at tlie 

 close of the entire work, we think it best to print such notes as are 

 likely to be immediately useful in this place, at the close of the 

 Acephala, and, at the same time, to correct some errors into which 

 we had inadvertently fallen. Additional memoranda on species 

 we shall reserve for our text explanatory of the plates, to be given 

 at the close of the work. 



TUNICATA. 



Although this order offers a rich harvest to the explorer of our 

 shores and seas, little more has been published in addition to the 

 account we gave in our first two numbers. In the valuable 

 catalogue of the " Marine Mollusca of Northumberland and 

 Durham," by Mr. Alder, that able naturalist, in conjunction with 

 Mr. Albany Hancock, has given descriptions of several new, 

 simple and compound Ascidians, which we here transcribe. 



SiDNYUM TURBINATUM. 



" A species, which we had always taken to be this, is not rare on 

 our coast, but it differs from that figured in Forbes and Hanley's 

 ' British Mollusca.' It is inversely conical, sometimes adhering 

 by a narrow base, and is of an orange-red colour, with the animals 

 vertically and concentrically arranged : their branchial apertures 

 are eight-cleft. The masses are of different sizes, from a quarter 

 to half an inch high, erect, and frequently clustered." — Ald. 

 Cat. p. 109. 



VOL. II. 3 n 



