•).) 
THE VOTAGE OF H.M.S. CHALLENGER. 
the extremity of a slight conical papilla in Spirula peronii (PI. III. aw.), whilst it is 
completely sessile in Spirula reticulata (Fig. R, viii). This anal opening has no filiform 
apiK'iulages, such jis arc found in other Dibranchiate Cephalopods. The intestine 
presents internally a longitudinal furrow bounded by two very distinct folds, as in all 
(’ephalopods examined in this respect (Fig. 0, i).^ 
The little iuk hag is situated veiitrally (PI. III., ik) in the bend formed by the 
intestine (Fig. R, iii) ; it opens into the intestine quite close to the anus. 
IV. Circulatory System. 
The heart is situated in the viscero-pericardial cavity towards the ventral aspect, in 
fn)iit of the sjiire of the shell and under the intestine and the kidneys (PI. VI. fig. 8). 
It IS (es[»ecially in the individual .of Spbrnla reticulata examined) very flat dorso- 
vrntndly ami jusymmetric (Fig. P) ; the ventricle is almost entirely placed at the right of 
the median line, while at the left is found only one prominence towards the branchio-cardiac 
ve.H,sel or auricle. 
fhntnatorir^ihr*, Si’fiiola, Srj/ia, Orfoptiti, Nautilus. A similar furrow has been met with in other 
i*, iM in c<*rtain KhipitlugloHsids (example, Trorlius). Rut in the initial portions of the intestine of 
there U a com*sj>on<ling longitiidinnl cushion (typhlosolis) : e.r/., in all the Laniellibranchs examined from 
thi> fi'iint of view (Ano<///ti/a, Anomia, Donar, (Jslrea), and the Gastropods, including the Pteropods (Paludina, 
Utlu, AnnruJa, Tritonia, Artspim, Liinarina, Clio), and Chiton among the Amphineura. In all these 
the inlextine being much ndlc4l up, it isdilFicult to <letcrminc the morphological position of this typhlosolis, 
hut in llw Cephalopoil*, where the intestine is only turned back and not twisted, wo can see that the 
furTow«-<l trphhiKilU occupies the <Ionial side, as is the case also for the organ of the same name known in 
*. .< OIi^- ‘ It is then probable that the dorsal ciliated furrow of the intestine of Neomeniidaj also 
rr- *j»»nd* to it. 
VI 
Kic. O. — Trnnkverse section of the in- 
testine of .S<7>ui ; X 18 . i, longi- 
tniliiial furrow ; ii, intestinal epi- 
tbehum. 
Fio. P. — Heart of Spirula reticulata, ventral view ; 
X 4. i, right auricle ; ii, ventricle ; iii, pos- 
terior aorta ; iv, posterior pallial artery ; v, 
recurrent (genital) artery ; vi, left branchio- 
cardiac vessel (auricle) ; vii, anterior aorta. 
