166 PEOF, W. A. HEKDMAX ON FUNICULINA QUADRANGQLAEIS 



not sufficiently delicate in its shades and is not sufficiently gelatinous and 

 translucent in appearance. 



Alder *, in 1863, described a specimen from the Channel Islands which 

 seemed to bridge the gap between Diazona and Syntethys so effectually that 

 he placed Forbes and Goodsir^s species under Savigny^s genus as Diazona 

 Jiehidica, and he showed, moreover, that the living apple-green colour of his- 

 Guernsey specimen changed to violet on preservation in alcohol. The- 

 apertures of his specimen were obscurely 6-lobed, and consequently many 

 subsequent writers have considered all these specimens to be the same 

 species of Diazona, and the name " Jiehridica " has dropped out of use. The 

 animal has since been found repeatedly in the Mediterranean (at Naples and 

 elsewhere), off the coasts of Brittany, and near Plymouth. Garstang f, in 

 1891, pointed out some differences in detail between specimens from Plymouth 

 and the description given by Forbes and Goodsir, and suggested the possible 

 specific distinctness of the Hebridean form (D. hehridica) from all the rest 

 (D. violacea). He concludes with the remark : " the whole matter is so beset 

 with doubts that it is greatly to be desired that specimens should be obtained 

 again from the Hebrides, and their anatomy re-described." Following upon 

 this I published % a brief note upon a Hebridean Diazona dredged off the 

 north coast of Mull by the late Duke of Argyll, and sent to me for identifi- 

 cation through Sir John Murray. I showed in this paper that all the supposed 

 points of difference between the Mediterranean Diazona and the Hebridean 

 Syntethys can be bridged over by examining in detail a sufficient number of 

 uscidiozooids. Neither in the lobing of the apertures nor in the minute 

 anatomy of the branchial sac can any constant character be found which will 

 enable us to divide the specimens I have examined into two sets, " hehridica '' 

 and " violacea." The question of colour I shall return to below. 



In recent systematic works on the Tunicata, such as Bronn^s ' Thier-reich ''' 

 (1909), and 'The British Tunicata,' by Alder and Hancock (Ray Society,. 

 1912), Syntethys hehridicus has been accepted as a synonym of Diazona 

 violacea, but probably without any further examination of Hebrideaui 

 specimens. 



Now we turn to the new material. While dredging from the ' Runa '" 

 this summer, specimens of Diazona closely resembling Forbes and Goodsir's 

 Syntethys were found, as follows : — 



(1) August 7th, a few miles south of Barra Head, in the Atlantic,, 

 60 fathoms, one large colony measuring 9^ x 7i x 5 inches, and of a. 

 beautiful translucent pale green colour. 



* Ann. & Mag. Nat. Hist. (3) xi. p. 169, 



t Journ. Mar. Biol. Assoc, for May 1891, p. 47. 



X Ann. & Mag. Nat. Hist, for Aug. 1891, p. 16o. 



