32 BRITISH TUNIC ATA. 



muscular band. Oral filament* numerous, well deve- 

 loped, with the points attenuated. 



Length [sometimes] an inch and three quarters, but 

 usually smaller. 



Hcib. [Between tide-marks and] at low water. 



SCOTLAND. - Tobermorey, Mull, associated with 

 Ascidia rubicunda and adhering to Plocamium cocci- 

 neum (Norman). 



IRELAND. Roundstone Bay, Comiemara, Galway, in 

 clusters attached to the test of Ascidia Normani 

 (More). 



First record. Hancock, 1870 ; coll. Norman, 1866. 



The test of this species (PI. XXII, fig. 10) is so 

 perfectly hyaline that when immersed in water it is 

 difficult to observe its form ; and usually the shrivelled 

 yellowish mantle suspended within by the attachment 

 of the tubes is so conspicuous that it is hard to believe 

 that it is surrounded by the outer tunic. This is the 

 case with specimens preserved in spirit ; the brilliancy 

 then, of this creature, may be increased in a living state, 

 united as it is in clusters, and with the mantle fully 

 expanded and imparting to the mass a delicate 

 yellowish hue, intensified towards the base or visceral 

 nucleus. When attached to Algas, as it appears fre- 

 quently to be, the base is much contracted, and then 

 the body is decidedly ovate or pyriform with the upper 

 end rounded and inflated. But the specimens which 

 are adherent to a flat surface have the lower or basal 

 portion a little more spread, and in these the form is 

 more definitely ovate. The vascularity of the test 

 seems limited to the lower portion. 



The mantle (see PI. XXII, fig. 10) lies free within 

 the test, being attached to it only at the tubes and 

 towards the base where the vascular trunks enter it. 

 It is delicate and transparent, and appears to be 

 highly contractile ; the muscular fibres are, however, 

 far from being robust ; they are most developed on the 

 right-hand side, and, like those in the other two 



