AND ACCOUNT OF A NEW SPECIES OF SEPIOLA. 83 
dices do not exist on the branchial auricles of Loligopsis, where the branchie are single 
on each side as in other Naked Cephalopods. They consist here of a soft, white, fleshy, 
round mass, attached by a very short broad peduncle, flattened outwardly and concave 
in the middle, but without any internal cavity or any communication with that of the 
hearts, to which they are attached. The branchial hearts', or the two portions of the 
divided auricle of this class, have here the usual position at the base of the branchie, 
on each side of the systemic heart, and propel the venous blood along the margin of 
the ligament connecting each gill to the sides of the mantle. The branchie2 have the 
usual structure and attachments, and each contains about twenty pectinated lamine on 
each of its sides. The form of these pectinated branchie of Naked and Testaceous Ce- 
phalopods, and their lateral position under the open mantle, correspond strikingly with 
those of Pectinibranchiate Gasteropods, and have also obvious affinities with those of the 
Cyclostome Fishes. They are double in these Gasteropods as in Nautilus, but are de- 
veloped only on the left side, the right side being occupied with the terminations of the 
digestive and the genital apparatus. These passages in Nautilus and in the Naked Cepha- 
lopods terminate on the median plane under the funnel, and thus allow the two sides of 
the body to become symmetrically developed, as in the higher classes of animals. The 
arterialised blood coming along the free margins of the branchie in two very capacious 
veins, is poured into the systemic ventricle at points not corresponding on the two sides. 
The systemic heart? is of a lengthened compressed form, placed transversely between the 
lateral hearts, and anterior to the stomachs : it is broadest in the middle, and tapers regu- 
larly to the two extremities, which terminate in vessels of a very different nature. The left 
apex of the systemic ventricle receives the left branchial vein, which, as well as the right, 
is a little dilated before it enters the heart*. The right branchial vein, however, enters 
this ventricle about a third from its right apex, and on its anterior aspect. The right 
apew of this lengthened fusiform heart gives origin to the great dorsal ascending aorta*® 
which winds round on the right side, behind the liver and esophagus, to ascend to the 
head, along the middle of the back of the mantle. About a third from the left extremity 
of the systemic heart, and from its lower margin, comes off the anterior descending 
aorta®, which immediately gives off two large lateral trunks’ to the great glands of the 
oviducts and to the ovary, and then bends forwards to ascend and ramify upon the an- 
terior parietes of the mantle. The form of the systemic ventricle varies remarkably in 
the Naked Cephalopods, as well as the direction in which it is extended ; but there is great 
uniformity in the distribution of its vessels. Most generally it is extended transversely 
across the body, receiving the arterialised blood by a single branchial vein on each side, 
and sending out a large dorsal aorta, which ascends to terminate in the head, and a smaller 
descending aorta, which bends forwards, after supplying the genital apparatus, to termi- 
nate on the ventral surface of the mantle. In Nautilus, where the branchié are double 
on each side, this ventricle receives the blood by four venous trunks instead of two. 
Fig. 9c.c *Fig.9.f.f. °Fig.9.i 4 Fig. 9k. ° Fig. 9k. © Fig. 9.0. 7 Fig. 9. m. 
M 2 
