REPORT ON THE PTEROPODA. 
27 
The Mantle . — The pallial gland, so far as I was able to observe on the badly pre- 
served specimen at my disposal, presents the same appearance as that of Gleba . It is 
clearly asymmetrical, and is divided by a transverse band, also asymmetrical, as in the 
other Cymbuliidse. 
The aperture of the pallial cavity also exhibits the asymmetrical disposition already 
noticed in Cyrnbulia, and the pallial cavity has the same extent as in this latter genus. 
The Digestive and Generative Organs . — As in Gleba, neither a buccal mass nor 
hornv structures in the mouth are to be found. The digestive and generative organs 
are similar on the whole to those of Gleba, and consequently to those of Cyrnbulia. The 
terminal portion of the intestine is clearly directed towards the left side of the median 
line. 
The visceral mass, which as in these two genera is suspended freely in the pallial 
cavity, presents at its aboral aspect a rather thin prominent ring. It resembles a sucker 
in form, and I am unable to give any adequate explanation of its function. 
Die Circulatory and Excretory Organs . — The heart and the kidney have the same 
situation and mutual relations as in the other genera of the family. 
The Nervous System also is disposed as in Cyrnbulia and Gleba, that is to say, the 
visceral commissure is composed of three closely-placed ganglia. This special conforma- 
tion of the visceral commissure, then, is a very definite character of the family Cymbu- 
liidse, and is only shared by the genus Peraclis. 
The cerebral ganglia are slightly segmented as in Cyrnbulia, and the pedal ganglia 
do not differ from those of this genus. The otocysts too are disposed in the same 
manner, and the innervation of the various organs is quite similar. 
3. Gleba. 
Die Head differs from that of Cyrnbulia in being free, and projecting in the form of 
a more or less elongated proboscis in front of the fin. The tentacles are quite similar 
to those of Cyrnbulia, and are situated in the same position, so that in those forms which 
have an elongated proboscis they are a long way behind the mouth. 
As in the preceding genera, the opening of the copulatory organ is situated a little 
posterior to the tentacles and in the middle line in the adult, whilst in very young 
individuals it is placed a little towards the right side (PI. III. fig. 12, b). 
Die Foot forms a very large natatory disc with even margins, and having neither a 
space devoid of muscular fibres at the lateral extremity of the dorsal margin, as in 
Cyrnbulia, nor a ventral appendage. During development this appendage exists and is 
very long, but it becomes much reduced in the older larvae (PI. III. fig. 12, c ), and 
disappears entirely in the adult. 
The Mantle has on the whole the same disposition as in Cyrnbulia, except that the 
