SOME ASOIDIANS FROM THE ISLE OP WIGHT. 141 



Ascidia marioni both in the position of the cloacal aperture and in the 

 minute tuberculation of the surface, it is not improbable that the two 

 are specifically identical ; but whether Heller's individual was rightly 

 referred to Alder's species or not is very doubtful. Alder's rudis 

 possessed " small, distant tubercles" on the test, and was "sometimes 

 nearly smooth," — a condition very different from that in Heller's 

 specimen, as well as in Roule's A. marioni. 



Tf, as I believe it will now be generally admitted, the forms described 

 by Heller, Roule, and Herdman under the name Ascidia depressa can 

 no longer lay claim to that title, it will be necessary to refer to them 

 under new designations. I would propose for the Mediterranean species 

 described by Roule the name Ascidia Roulei. To the variety petricola 

 of this species, Heller's specimen almost certainly belongs. I believe 

 that Ascidia Roulei is closely related to, if not identical with Alder's 

 Ascidia rudis : but it is impossible to give a final decision upon this 

 question until our British Ascidians have been collected and re-examined 

 in greater detail.* 



The form described by Herdman as Ascidia depressa, in the paper to 

 which reference has been made above, appears to be distinct from 

 Ascidia Roulei, although it is impossible, from the want of cor- 

 respondence between the descriptions, to speak decisively. But Prof. 

 Herdman has himself thrown doubt upon their identity in his recently 

 published! Revised Classification of the Tunicata, so that a new name 

 is, at least provisionally, desirable. I therefore propose for it the 

 name Ascidia Herdmani. 



The subjoined synonymic lists show briefly the conclusions to which 

 I have been led by the study of this species from the Isle of Wight. 



1. Ascidia depressa, Alder, 1848, loc. cit. 



= Ascidia depressa, Garstang, 1891 (the present paper). 

 ?? = Phailusia pussilla, Traustedt, 1883, loc. cit. 

 non Ascidia depeessa, Heller, 1875, loc. cit. (= J..-RowZei,Garstang,1891). 

 nee — — Herdman, 1881, loc. cit. ( = A. Herdmani, 



Garstang, 1891). 

 nee — — Roule, 1884, loc. cit. (A. Roulei, Garstang, 1891). 



* It is needless to say that we look forward with interest towards Prof. 

 Herdman's promised re-description of some of Alder and Hancock's types. 



t Journ. Linn. Soc. Zool., vol., xxiii, 1891, p. 594 



