30 BRITISH TUNICATA. 



hand side ; these and the sphincter belts of the tubes, 

 together with a few short, longitudinal fibres near the 

 orifices, complete the muscular apparatus of this organ. 



The branchial sac is short and subquadrate, with 

 the spirals comparatively few and large, arranged 

 with some little degree of irregularity in 1 2 or 14 

 transverse rows ; the larger spirals have about 5 or 6 

 coils, and they seem set in square areas, defined by 

 the primary vessels and stout longitudinal secondary 

 ones, in the same manner as in C. par allelogr ammo,. 

 The oral filaments are minute and correspond in 

 number and position with the primary vessels; there 

 are consequently not more than 12 or 14 of them. 

 The branchial tubercle is apparently tubular, much 

 restricted in length, and with a trilobed orifice at the 

 free extremity, the upper lobe being the longest. 



The alimentary canal is disposed much as it is in 

 C. parallelogramma; the stomach is however a little 

 more elongated ; the oesophagus is rather long and 

 narrow, and opens by a widish mouth near to the 

 bottom of the branchial sac at the ventral niargin ; the 

 intestine turns downwards at the dorsal margin, and, 

 advancing along the bottom of the mantle, turns up 

 the ventral margin attached to the branchial sac, and 

 terminates at the base of the excurrent tube not far from 

 the top of the sac ; here it opens into the atrium by a 

 wide orifice with the margin reflected and pectinated. 



The ovary is a tabulated or tubular organ, spread 

 over the right-hand side of the stomach, passing round 

 the margin, and appearing at the left-hand side ; the 

 oviduct is wide, accompanies the intestine to its 

 termination, and appears by the side of the anus. 

 The male organ is spread over the posterior extremity 

 of the left-hand side of the stomach and the intestinal 

 loop ; it is composed of minute, slightly-branched 

 caaca ; the vas deferens follows the oviduct to the 

 atrium, and then, advancing a little beyond its termin- 

 ation, becomes adherent to the branchial sac, and opens 

 some short distance in front of the anus. 



