ASCIDIA MOREL 



( 



opaque white. The muscles are strongly developed and 

 glisten amidst the spots of colour. The oral lamina 

 (PL XIV, fig. 6) has the cleft in front short; it is widened 

 a little at the mouth and terminates rather abruptly 

 immediately below it. Above the mouth, on the left- 

 side, there are three or four oblique plaits ; there is no 

 denticulation at the side. It is usually more or less 

 coloured with brilliant carmine, particularly at the base 

 and in the vicinity of the mouth ; the sides are paler, 

 the pale tint being continued to the margin. The ten- 

 tacular filaments are about forty in number ; they are 



Position 



of 

 oral lamina. 



Position 



of 

 endostyle. 





FIG. 23. Part of the branchial sac of Ascidia Morei, highly magnified. 



closely set, colourless, hyaline, and are dotted with 

 opaque white. The branchial tubercle (PI. XIV, 

 fig. 3) is well developed, angular at the sides, lozenge- 

 shaped, and the convolutions are rather peculiar. 



The primary blood-vessels of the branchial sac are 

 very regularly disposed and do not vary much in size. 

 The secondary blood-channels are peculiar ; they are 

 exceedingly wide and irregular, the stomata being 

 short, elliptical, and irregular in size. They rarely 

 reach the whole width of the space between the 

 primary vessels, and are not infrequently quite 

 minute; the result is that the whole of the tissue 

 has the appearance of a perforated membrane which is 



