28 



PHYLUM TUNICATA (UROCHORDA). 



Pharynx without internal longitudinal bars, stigmata small and irregular, 

 dorsal lamina as a membrane, viscera on dorsal edge of pharynx. 



Hypobythius Moseley, stalked, test thickened in places to form plates, 

 600 to 3,000 fms. 



Fam. 2. Cynthiidae. Usually attached, rarely free, sometimes pedun- 

 culated ; mouth aperture usually 4-lobed, atrial 4-lobed ; pharyngeal wall 

 longitudinal!} 7 folded, internal longitudinal bars without papillae, stig- 



FIG. 20. A Portion of the pharyngeal wall of Bathyoncus mirabilis, B of Culeolus wyville- 

 thomsoni (from Bronn, after Herdman). il inner longitudinal bar ; kf folds of pharyngeal 

 wall ; ks pharyngeal apertures ; Ig longitudinal bars ; tr transverse bars. 



mata straight ; tentacles simple or branched ; intestine on the left side, 

 only slightly or not at all attached to the mantle ; gonads on the inner 

 surface of the mantle, either on both sides or on one only. In the genera 

 Culeolus, Cystingia and Fungulus, etc., the stigmata are large and quad- 

 rangular, and fine longitudinal bars are supposed to be absent (Fig. 20). 

 It is doubtful however if this interpretation is correct (see r>. 12). 



FlG. 21. Filaments of the tunic of Molgula roscovita, showing the swellings to which the 

 grains of sand are attached (from Delage and Hrouard, after L.-Duthiers). 



Sub-fam. 1. Bolteninae. Pharynx with more than 4 folds on each 

 side ; tentacles compound ; body on a long stalk. Boltenia Sav. (Fig. 

 19), pharynx wall with the fine longitudinal bars, stalk arises on 

 ventral surface near mouth, N. Atlantic, Australasia, Arctic. Cys- 

 tingia MacLeay, the transverse and longitudinal bars of the pharynx 

 form a loose meshwork, fine longitudinal bars absent, Arctic. Fun- 

 gulus Herd., pharyngeal walls with square meshes, no fine longitudinal 

 bars, stalk short and thick, dorsal lamina as a membrane, abyssal 



