72 BRITISH TUNICATA. 



The single ganglion of the nervous system of 

 A*fi<Ua is, as usual, placed between the respiratory 

 tubes. It lies in a blood-sinus situated between the 

 inner tunic and lining membrane. It is fusiform, 

 varying little in character, and is partially folded in a 

 much folliculated gland-like substance, as determined 

 in A. merit/ill (figs. 10 and 11, p. 50) and in some other 

 species. Three or four nerves are given off from each 

 extremity, all of which go to the respiratory tubes ;ni<l 

 to the adjacent portions of the inner tunic or mantle. 

 A branch from one of the principal nerves has been 

 traced to the branchial tubercle. 



1. Ascidia mamillata Cuvier.* 



(PI. I, and fig. 13 in text.) 



mamillata CUVIER [Mem. Ascidies in Mem. clu Mus. 

 II (1815), p. 30, pi. iii, and Mem. Asc. p. 22, pi. iii, in] 

 Mem. cles Moll. (1817) ; LAMARCK Hist. Nat. Anim. sans. 

 Vert. ed. 1, III (1816), p. 125 ; ed. 2, III [1840], p. 532. 

 Phalln.yin inn HI tUata &AVIGNY Mem. Anim. sans. Vert. pt. 2 

 (1816), p. 168. 



FORBES in Brit. Moll. I [1848], p. : >2. 



I >< n] H oblong-ovate, opaline, white or yellowish, 

 mamillated with unequal rounded eminences. Aper- 

 tures, branchial terminal, anal about one-third down, 

 generally terminating on the left side ; ocelli incon- 

 spicuous. Trxf thick, firm, and cartilaginous, smooth, 

 and of a porcelain-like lustre, more or less marked 

 with delicate branched or net-like lines. Man fir dark 

 blue. Tentacular filaments few and rather small. 

 Branchial sac with rather broad papillae. [Oral 



: The habitat and first British record of each species have been added 

 when ascertainable ; if from the anthers' MS., without indication of inter- 

 polation ; if from other sources, inserted within brackets. As the localities 

 are not in any definite order in the MS., they have been rearranged through- 

 o\it, referred (with the exception of districts and well-known islands) to 

 their counties, and grouped under the different countries of the British 

 Isles. No addition has been made, cither to the synonymy or localities, 

 from information published more recently than 1870. 



