REMARKS UPON APPENDICULARIA AND DOLIOLUM 7 1 



sented by a richly ciliated band or fold (^) of the inner tunic, which 

 extends from the opening of the mouth forwards, along the ventral 

 surface of the respiratory cavity, to nearly as far as the ganglion ; 

 when it divides into two branches, one of which passes up on each 

 side, so as to encircle the cavity (f). This circlet evidently represents 

 the " ciliated band " of Salpa. 



The mouth (^g) is wide, and situated at the posterior part of the 

 ventral paries of the respiratory chamber. The oesophagus {It) short, 

 and slightly curved, opens into a wide stomach (z) curved transversely, 

 so as to present two lobes posteriorly. 



Between the two lobes, posteriorly, the intestine (Ji) commences, and 

 passing upwards (or forwards) terminates on the dorsal surface just in 

 front of the insertion of the caudal appendage (/). 



The heart lies behind, between the lobes of the stomach. I saw no 

 corpuscles, and the incessant jerking motion of the attached end of 

 the caudal appendage rendered it very difficult to make quite sure 

 even of the heart's existence. 



83. Mertens describes a vascular system, consisting of an aortic 

 vessel, which runs forwards on the dorsal surface, and of a principal vein 

 of a red colour, which passes to the ventral surface, and there divides into 

 three branches, one of which runs forwards to the " semicylindrical 

 body " (ganglion ?), and the other two pass to the dorsal region. 



A circular canal communicating with the aortic vessel exists, he 

 says, on each side of the anus, and is connected with the ventral 

 vessel by means of a vessel, through which no corpuscles were seen 

 to pass. 



I have seen nothing of this vascular system. The caudal appendage 

 (A) is attached or rather inserted into the body on the dorsal surface 

 just behind the anus. It consists of a long, apparently structureless, 

 transparent, central axis (in), rounded at the attached, and pointed at 

 the free end. This axis is enveloped in a layer {o) of longitudinal, 

 striped, muscular fibres ; which form the chief substance, in addition to 

 a layer of polygonal epithelium cells, of the broad alary expansion on 

 each side of the axis. 



I did not observe the lateral canal containing air, described by 

 Mertens. 



84. The only unequivocal generative organ I found in Appen- 

 dicularia was a testis (/), consisting of a mass of cells developed 

 behind and below the stomach, enlarging so much in full-grown 

 specimens as to press this completely out ot place. 



In young specimens the testis is greenish, and contains nothing 

 but small pale circular cells ; but in adults it assumes a deep orange*'- 



