18 BRITISH TUNICATA. 



For specimens of tins very distinct and interesting 

 species we are indebted to Mr. A. G-. More, who col- 

 lected it in considerable abundance in Kilkieran Bay, 

 (Jonnemara, in 1869. The specimens were for the 

 most part united towards the base into dense clusters, 

 the upper portions being quite free. The aggregation 

 is produced by the agency of the papillae, which clothe 

 the sides of the basal extremity of the test ; the attach- 

 ment is consequently lateral. The common mass had 

 apparently been fixed by the same means to some 

 foreign bod} 7 . 



Genus 3. CORELLA Alder & Hancock, 1870. 



[Ascidia (pars) 0. F. MULLER Zool. Daiiica, II (1788), p. 11.] 

 [Phallusia ML-RKAY in Proc. R. Soc. Edinb. IV (1859), p. 



149.] 

 Corella ALDER & HANCOCK in Aim. Nat. Hist. [(4) VI 



(1870), p. 362]. 



Body subquadrate, rounded, or ovate, coriaceous, 

 very slightly contractile, rather compressed, attached 

 mostly by the base. Apertures as in Ascidia, the bran- 

 chial 8-lobed, the atrial 6-lobed, each with small ocelli. 

 Test smooth and diaphanous. Mantle often brightly 

 coloured. Tentacular filaments linear, unbranched. 

 liraiK-ldal sac with the meshes regularly and beauti- 



O e/ 



fully convoluted, framed in squares formed by stout, 

 secondary rectilinear vessels and the primary trans- 

 verse vessels. Viscera sinistral, the stomach placed 

 low, with the intestine bending backwards and down- 

 wards on the left side, passing along the base of the 

 mantle, and rising in front to the anal aperture. Ee- 

 productive organs on both sides, the oviduct following 

 the line of the intestine. 



The above genus was characterized when only a 

 single species was known, namely the so-called Ascidia 

 parallelogramma, which differs in so many important 

 characters from the species with which it was associ- 



