/O REMARKS UPON APPENDICULARIA AND DOLIOLUM 



separating this from the species observed by Mertens are not to my 

 mind sufficient to form the basis of any specific distinction, and as the 

 description given by MM. Quoy and Gaimard, and by Chamisso, are 

 too imperfect to estabhsh any certain distinguishing characters in their 

 case either, I shall consider that only one species has been observed. 

 And as I can see no reason for the construction of a new and by no 

 means euphonious name by Mertens, I shall retain both the generic 

 and specific names given by Chamisso, Appendicularia flagelluni 

 (Chamisso), Syn. Oikoplciira Chainissonis (Mertens), Oikopleura bi- 

 furcata (Quoy and Gaimard). 



80. The animal has an ovoid or flask-like body, Plate XVIII. 

 [Plate 8] fig. i, one-sixth to one-fourth of an inch in length, to which 

 is attached a long curved lanceolate appendage or tail, by whose 

 powerful vibratory motions it is rapidly propelled through the water. 



The body frequently appears wrinkled and crumpled externally, and 

 its upper, smaller extremity has rarely clear and well-defined edges. 

 The lower part of the body is frequently separated from the upper by 

 a slight cleft or constriction, fig. 4, and it is here that Mertens places 

 the orifice of the mouth, supposing indeed that the upper part of the 

 body plays the part of a maxilla ! 



81. The smaller extremity of the animal is perforated by a wide 

 aperture {d) which leads into a chamber, which occupies the greater 

 part of the body, and at the bottom of this chamber is the mouth. 

 The chamber answers to the respiratory cavity of the Tunicata, and is 

 lined by an inner tunic distinct from the outer ; the space between 

 these, as in the Salpa, being occupied by the sinus system. 



On the side to which the caudal appendage is attached, an endostyle 

 ic), altogether similar to that of the SalpcB, lies between the inner and 

 outer tunics ; and opposite to this, or on the ventral side, close to the 

 respiratory aperture, there is a nervous ganglion, to which is attached 

 a very distinct spherical auditory sac, containing a single, also spheri- 

 cal, otolithe. The sac is about Y^^h of an inch in diameter. The 

 otolithe about ^ troth, figs, i, 2, 4 «. 



Anteriorly, a nerve is given off from the ganglion {a) which becomes 

 los about the parietes of the respiratory aperture ; another large trunk 

 passes backwards {U) over the left side of the oesophagus, and between 

 the lobes of the stomach, until it reaches the appendage, along the 

 axis of which it runs, giving off filaments in its course, fig. 2. I did 

 not observe anything resembling the " languet " of the Salp(B ; but 

 Mertens describes two leaf-like laminae existing, one on each side of 

 a " semicylindrical " body, which seems to be the nervous ganglion. 



82. There is no proper branchia ; but that organ seems to be repre- 



