KUNGL. SY. VET. AKADEMIENS HANDLINGAR. BAND 52. N:o (6. 95 
pulmonary orifice (s.) which is situated in the peripedal furrow above the anus (a). 
The outer pulmonary sac stretches along the right side of the pericardium (and partly 
covers it); in its posterior end it becomes narrow and communicates here with the 
posterior or respiratory portion of the lung, which is intimately connected with the 
nephridium (n.) in the same manner as in Oncidiidae (cf. PLATE 1893). From the 
nephridium, which occupies an orbicular space behind and on the sides of the pericar- 
dium (even below the outer pulmonary sac), the reno-pericardial canal (p.t.), on the one 
hand, leads to the pericardium, where it debouches on the right side of the auricle, 
a.) S. 
Fig. 51. Mantle organs of Atopos australis(?): a cloaca (anus 
and urethra pore); h. ventricle of the heart; J. lung; n. nephri- 
dium: p. pericardium; p. t. pericardial tube of the nephridium; 
s. pulmonary orifice; wu. urethra. 
and on the other hand, a urethra (w.) runs along the posterior and outer side of 
the outer pulmonary sac; this urethra joins the rectum, thus forming a cloaca just 
as in Oncidiidae (cf. PLATE 1893). 
It should be remarked that the above account of the organization is based 
on the dissection of only a single specimen. I regret that no more material of this 
interesting form has been at my disposal for examining the finer details in sections. 
Just in the anatomy of the mantle organs and their mutual relations are the chief 
points for judging on the affinities to be found. At present no exact idea of the orga- 
nization is obtainable from the discrepant descriptions of Atopos given by SimrotTu 
on the one hand and by P. & F. Sarasin on the other, which both differ from 
the above statements. The two Sarasin give a somewhat schematic figure of the 
mantle organs (fig. 141), but they do not mention anything about the heart and the 
nephridium. As to Srmrorn’s description, they make no attempt at comparing 
it with their own results nor enter into a criticism of it. They only see in the 
urethra gland, existing in the form examined by them, something equivalent to his 
