APPENDIX. 245 



taken. Testis white, ramifying on the surface of the ovary; the 

 vas deferens runs up on the oesophagus and rectum to the side of 

 the anus. The heart is in the loop of the intestine and ovary. 



Sp. Syntethts Hebbidicus. — All the specimens were dredged 

 in thirty fathoms water, close to Croulin Island, near Applecross. 

 The locality in which they occurred is remarkable for the assem- 

 blage of boreal mollusca there congregated, so that we may reason- 

 ably expect that this extraordinary Ascidian will be found here- 

 after in the Norwegian Seas. It is probably a member of the 

 boreal type of the British fauna. It was discovered by Mr. M'An- 

 drew. A detailed account and figures of it are contained in the 

 "Transactions of the Koyal Society of Edinburgh" for 1851. 



The genus Syntethys is intermediate between Diazona and Cla- 

 velina. The only known species forms compact greenish translu- 

 cent gelatinous masses of half a foot in diameter, and nearly 

 equal height, affixed to rocks or stones by a short base. The 

 individual Ascidians are, when full grown, two inches in length. 

 Their inner tunics are remarkably irritable, withdrawing them- 

 selves into the common mass when pinched. 



Mr. Couch, some years ago, laid before the British Association 

 at Plymouth, gelatinous masses very similar to the Syntethys 

 from deep water off the coast of Cornwall. These have proved to 

 be compound Ascidians, and are now under examination by Mr. 

 Huxley, who has undertaken the investigation of this curious 

 group of Mollusks. 



APPENDICULARIA. Chamisso. 



When cruising off the north coast of Scotland in 1845, with 

 our friend, Mr. M 'Andrew, we were attracted by the appearance 

 of cloudy patches of red colouring matter in the water, and on 

 procuring some we found, on submitting it to microscopic obser- 

 vation, that it consisted entirely of the bodies of the curious and 

 anomalous creature called Appendicularia. The circumstances 

 under which they were taken, and the profusion of objects of 

 more immediate interest, prevented our doing more at the time 

 than making a slight sketch of their form and colouring. 



In a very interesting memoir published in the " Philosophical 

 Transactions" for 1851, Mr. Huxley has given a fresh and full 

 account of the anatomy of this curious type, for whose observation 



