ASCIDIA. 147 



On the upper portion of this animal, a younger specimen was seated 

 in slight adhesion. The orifices were proportionally somewhat more ap- 

 proximated than in fig. 5 ; which shews that the disproportion is in the 

 ratio of the age. — Fig. 6. 



These specimens did not survive above a month. 



The adhesion of such Ascidia? as the mentida and rustica, sustained 

 on the base, is rather an intimate application, like that of the Lob/daria, 

 than by union or incorporation of the parts. Yet it is difficult to detach 

 these specimens without laceration. The reverse is seldom practicable, 

 which renders all very liable to perish. 



Though I have preserved a multitude of some of the preceding species, 

 with all possible care throughout, very little of their nature has been dis- 

 closed : Nor has any success attended my anxious endeavours to discover 

 their formation in the earliest stages. This will, no doubt, seem very sin- 

 gular. It is one example of the disappointment in a search after interest- 

 ing points of zoology, even where subjects are abundant. 



When first obtained, all specimens, if intended for permanent obser- 

 vation, should undergo careful inspection, that it may be seen they are 

 free of external injury. None, unless perfect, need to be retained. Do- 

 ing so would be superfluous trouble. 



Plate XXXVI. Fig. 5. Ascidia mentula. 



6. Ascidia mentida, young. 



§ 6. Ascidia papilla. — Plate XXXVII. Figs. 1-11. — Farther 

 than ascertaining the external formation and a few — very few of the habits 

 of the Scotish Ascidiae, I cannot affirm that the care and attention bestowed 

 by me on them, have been rewarded by much success. Perhaps an ani- 

 mal permanently rooted to the same spot, whose senses are so obtuse, that 

 possession of one only is definitely evinced, whose shape never changes, 

 and which appears to have little more than a mere passive existence, may 

 be said to be scarcely susceptible of displaying any thing else. 



The internal organization of the various species, as shewn by the skil- 



