REPORT ON THE TUNICATA- 301 



a toothed dorsal lamina (see PI. VI, fig. 5). The other 

 specimens have the organ in the usual condition. 



One of the specimens shows very distinctly the peculiar 

 arrangement of tentacles which I figured in 1880,* and which 

 is rarely seen in the species, viz., the larger tentacles spring- 

 ing from a point distinctly posterior to the line of origin of 

 the smaller series. This specimen has also a good deal of 

 dark brown pigmentation in the prebranchial zone at the 

 anterior extremity of the endostyle, and the greater part of 

 the prebranchial zone is papillated. 



Ascidia depressa, Alder and Hancock. 



Two specimens of this species were found attached to the 

 under surfaces of stones near low water, on the shore at 

 Bay-ny-Carrickey, Isle of Man. One has the body short, 

 while in the other it is elongated antero-posteriorly. The 

 difference is due chiefly to the size of the branchial siphon, 

 which is in the latter case, drawn out to a great length. 



I may add to the description of the internal structure of 

 this species published previously,! that the smaller inter- 

 mediate papillae upon the internal longitudinal bars of the 

 branchial sac are not invariably present. In the Manx 

 specimens they are seen in some meshes, and not in others. 



Ascidia prunum, 0. F. Mtiller. 

 Forbes, in his Malacologia Monensis, records this species 

 as being frequent on the Manx shores. As it has not been 

 found since, it is possible that Forbes may have confused it 

 with Ascidia scabra, or Ascidia virginea. 



Corella parallelogramma, 0. F. Miiller. 



Ascidia parallelogramma, Forbes and Hanley, Brit. Moll., 

 V. i, p. 34. 



Two specimens of this most beautiful species were 



* Journ. Linn. Soc, Zool., vol. xv, pi. xix, fig. 4. 

 t Herdman, Journ. Linn. Soc, Zool., vol. xv., p. 287. 



