CYNTHIA. 41 



13. 0. AGGREGATA, Rathke. (Sp.) 



Ascidia aggregata. Rathke, Zool. Dan. t. 130, f. 2. " 



Plate D. f. 5. 



Body bottle-shaped, cylindrical, with terminal approximate 

 orifices ; base of attachment small, sending out many fibres ; 

 outer tunic membranous, smooth, of an uniform brilliant orange ; 

 the orifices quadrangular, bordered with still brighter orange and 

 edged with red ; the anal placed more obliquely than the bran- 

 chial : no ocelli. About an inch in height. 



Gregarious in vast numbers under large stones in twelve 

 fathoms water at Dartmouth, R. M'Andrew and E. F. (184G.) 

 Sometimes forming large free bunches, in consequence of the 

 interlacing of the rootfibres. The description in the "Zoologia 

 Danica" well expresses this habit: — " Siquidem nunquam solita- 

 riam, semper vero plures, saepius viginti ad triginti, mediantibus 

 radiculis tendineis invicem junctas deprehenderit, eam aggrega- 

 tam appellari voluit." 



On many of the branching root-fibres are small, tough, globular, 

 imperforate, orange bodies, of various sizes, full of granules. Are 

 not these intermediate states of this Ascidian 1 The Ascidians 

 we examined were full of tadpoles in various stages of develop- 

 ment. 



This form seems intermediate between the simple and social 

 Ascidians, and should probably rank as the type of a distinct 

 genus. 



VOL. I. 



