438 FELONAIA, A NEW GENUS OF TUNICATED MOLLUSKS. 



spiratory sac, opposite to the branchial vein, performs the 

 function of a branchial artery. 



It is interesting to observe here the differences between 

 the modes in which the branches enter the branchial vein, 

 and strike off from the branchial artery. In the former, just 

 before the branches enter the trunk, they give off a number 

 of vessels, which enter the trunk alongside of their parent 

 trunk — the combination forming a sort of delta : in the latter 

 they leave the trunk singly, and send off their branches in a 

 radiating direction. At a little distance from the trunks of 

 both artery and vein, the secondary branches become parallel 

 to one another, and perpendicular to their primary branches, 

 the more minute divisions following the same mode of rami- 

 fication. 



Not having examined the animal when alive, we have no 

 information as to the nature of its blood. 



4. Nervous System. — This system consists, as in other As- 

 cidicv, of a ganglion situated in the substance of the mantle, 

 between the oral and anal orifices. It is globular, and sends 

 off nervous twigs — 1. To the respiratory orifice of the mantle, 

 2. To the respiratory sac, where it begins to exhibit the trans- 

 verse plaits, and 3. To the anal orifice of the mantle. 



5. Generative System. — The generative organs consist of 

 two elongated tubes, closed at one end, open at the other, 

 and having a great number of close-set parallel cseca, arranged 

 at right angles, and opening into them along each side. 

 These tubes are attached to the internal surface of the mantle, 

 their mouths free for a short distance, and prominent, the 

 rest of their extent and the attached coeca adherent. The 

 orifices of these organs are situate at the junction of the first 

 with the second quarter of the animal, and one-third of the 

 other end of each turns in towards its neighbour, and then 

 proceeds forward parallel to itself. The branchial vein runs 

 midway between the generative tubes, above, and the bran- 



