KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 52. N:o |6. 69 
into the stomach, and make it more closely related to the group Dendronotoidea 
(ELioT 1910), in which the liver is normally three-lobed. 
The nervous system (fig. 22) does not present any peculiarities; it seems to be 
of the same type as in the tribe Aeolidioidea, with some exceptions from the rule. 
Thus the ophtalmic nerves are rather long, and the ganglia olfactoria are situated 
within the peduncles of the rhinophores, from where they send nerve branches to 
the tubercles of the club. 
The kidney (n.) occupies a great part of the body, but has not such numerous 
branches as in Aeolidia (cf. HEcHTtT). It consists chiefly of a median, widened sac 
and lateral branches from it, passing forward on each side. The reno-pericardial 
tube is very wide, with the usual strongly folded walls. It opens to the right of 
the pericardium. 
The latter, as well as the heart (h.), is situated on the right side of the body. 
The genital organs (fig. 23). The hermaphrodite gland (g.) occupies the space 
between the stomach and the rectum; thus it is of comparatively small extension. 
The eggs are formed in the same folliculi as the spermatids, in their tops; the 
spermatids have long and narrow heads. — From the hermaphrodite gland runs a 
wide canal, in the present specimen filled with spermatids, which proves that these 
are mature before the ova; this hermaphrodite duct bifurcates into a male vas defe- 
rens (v. d.) and a female oviduct (o. d.). The former leads to the penis (p.) and 
receives immediately, before its junction with the penis sac, a duct from a large 
spermatocyst (or vesicula seminalis, v. s.). The female oviduct is short and debouches 
into the vagina (v.); here also opens a duct from a spermatocyst (receptaculum semi- 
nis, r. s.) as well as the outlet from the mucus gland (gl.) and the connected albumen 
gland. The penis opens somewhat in front of and below the female orifice. 
The whole apparatus is thus rather simply constructed and presents the diaulic 
type (in the sense of ELIOT), because the hermaphrodite duct furcates into two, not 
three canals. 
The presence of a vesicula seminalis in the male apparatus is a characteristic 
that distinguishes Madrella from the Aeolidioidea and gives it a resemblance to Tri- 
tontidae. In Marionia blainvillea as well as in Tethys fimbriata, VAYSSIERE (1901) 
has described a similar appendix to the male apparatus, which he names prostata; 
this is situated just beneath the proximal end of the vas deferens. This prostata 
also exists in Pleurobranchidae, in the Holohepatica, in Ascoglossa, and in the Den- 
dronotoidea (EL1ioTtT), but is absent in ÅAeolidiidae, Pleurophyllitdae and allies. The 
vesicula seminalis present in Madrella seems to be a homologon to this prostata 
gland or a further development of it. 
General remarks on the genus Madrella. Besides the present type the genus 
contains another species, M. aurantiaca, established by VAYSSIERE (1903) from the Gulf 
of Marseilles. A description of its anatomy is given, from which it appears that the 
cerata coptain liver diverticula, but have no nematocysts and do not present any knob- 
like dilations of their tips. The rhinophores, the jaws, and the teeth of the radula 
are very like those of M. ferruginosa. As ELioTt states about the latter species from 
