134 BRITISH TUNICATA. 



tremities irregularly pointed or rounded. The longi- 

 tudinal bars are well elevated, rather delicate, but 

 rigid, with the suspended membrane wide ; the papil- 

 lary membranes are well developed, with the thickened 

 margin rather narrow and not projecting so as to form 

 a papillary point. The oral lamina (PL XIX, fig. 11) 

 is wide, strongly ribbed on the right side and with the 

 margin entire ; it tapers gradually as it approaches 

 the mouth, which is not quite at the bottom of the 

 branchial sac, and terminates in a fine point a little 

 below it. The left oral appendages are very character- 

 istic : they are from 6 to 9 in number and are in the 



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form of pectinated, diagonal lamina? ; they vary some- 

 what in form, being either a little elongated and attenu- 

 ated at the ends, or short and more or less suddenly 

 produced ; and the number of the points varies from 

 one to four. The branchial tubercle (PI. XX, fig. 9) 

 is large and strongly involuted ; it is shield-shaped, 

 pointed below, wide and angulated at the sides above. 

 There are from 25 to 30 tentacular filaments ; they 

 are well developed, rather long and attenuated above, 

 with the base wide and blotched with opaque white, 

 and they are placed a little apart and are alternately 

 large and small. 



The intestinal loop forms an irregular oval mass 

 placed near the posterior extremity of the body and 

 towards the dorsal margin ; it reaches about half way 

 up the mantle ; the rectum diverges slightly and 

 terminates at the atrium a little in advance of the 

 loop ; the anal margin is narrow, smooth, and reflected ; 

 the oesophagus rather long. The greater portion of 

 the alimentary tube is of a delicate buff colour, and 

 the right side of the stomach is usually covered with a 

 dense, minute freckling of opaque white or yellow 

 matter ; the coating of A'esicular matter is thin and 

 the vesicles are minute and inconspicuous. 



The ovary is a tubular, branched organ confined to 

 the left side of the intestinal loop ; the extremities of 

 the branches, however, pass round the margins of the 



