Mr. W. T. C. Thomson on some Zoophytes and Polyzoa. 403 



XXXIII. — Notes on some Scotch Zoophytes and Polyzoa. By 

 W'yville T. C. Thomson, Sec. R.P.S., F.B.S.E., Lecturer on 

 Botany, King's College, Aberdeen. 



[With a Plate.] 



SlR, Bonsyde near Linlithgow, Jan. 12, 1852. 



In going over some of the Scotch Zoophytes and Polyzoa, I have 

 met with several species, partially described by Sir John Graham 

 Dalyell, in his 'Rare and Remarkable Animals of Scotland/ 

 Some of these species appear to be new, and others it is not very 

 easy, without a little consideration, to identify. Of one of the 

 former I send you a sketch and description ; of two others, Ser- 

 tularia fascis and Triticella flava, I hope to have something to 

 say shortly, but a few observations are still wanting. 



To Richard Taylor, Esq. 



Polyzoa infundibulata. 



Vesicularina. Fam. YesiculariaDjE. 



Avenella, Dalyell. 



Diag. Polypidom confervoid, filiform, very much attenuated, 

 creeping, nearly simple. Cells large, solitary, irregularly scattered, 

 sub-unilateral, slightly contracted towards the apex, curved. 



Animal an ascidian mollusk with from twenty to twenty-four 

 ciliated tentacula ; gizzard small. 



A. Dalyellii, Wy. T. Cells slightly rough with scattered, patent, 

 horny bristles. Plate XVI. B. 



Sir John Dalyell, in the 2nd vol. of his * Remarkable Animals/ 

 bestowed upon this mollusk provisionally the name of Avenella 

 fusca. " Fusca " is not a very appropriate specific name, as all 

 the species belonging to the genus, yet to be discovered, will 

 probably have an equal claim to the title. As Sir John has as 

 yet no namesake among a race whose manners and customs he 

 so carefully studied, I have taken the liberty of proposing in 

 preference the specific name "Dalyellii" a tribute due to his 

 labours in an obscure and unfrequented path. 



One of the largest and most conspicuous of our Vesicularian 

 Polyzoa, I have found Avenella Dalyellii very abundantly at some 

 seasonsamong the rejectamenta of the oyster dredges atNewhaven, 

 covering with dense tangled masses Thoa muricata, halecina, 

 Beanii, and other corallines from rather deep water. I met 

 with it once on Sertularia margareta, off Port Appin, Argyllshire, 

 and twice among rejectamenta from the Dogger Bank. 



The mollusk is, like all the rest of its family, very persistent. 



