DORIDOEIDES GARDINERIT. 289 
totheca could not be determined.” ‘The affinity between the 
two genera is therefore not close. In structure Doridoeides 
is more nearly allied to Pleuroleura (= Dermatobran- 
chus) but the general habitus and the configuration of the 
anterior parts and rhinophores is different, and unless 
intermediate links are discovered it is not clear that 
Doridoeides is either the ancestor or descendant of 
Pleuroleura. It must therefore be made the type of a 
new family Doridoeidide, the characters of which are at 
present the same as those of the genus, but the absence of 
oral tentacles, the narrowness of the radula and the denti- 
culation of the jaws are probably not of more than generic 
importance. ‘The family belongs to the Cladohepatica. Its 
only anomalous characters are the doridiform shape (which is 
really not very different from that of the Pleurophyllidide) 
and the presence of three genital openings. But, as Briiel 
observes (‘Geschechts- und Verdauungs-organe von Caliphylla 
mediterranea,’ Halle, 1904), although it is commonly stated 
that all the Alolidide are simply diaulic, the data available 
do not justify so comprehensive a statement. It is neverthe- 
less true that Doridoeides presents the arrangement of the 
genitalia which is typical of the Doridide, except that the 
second spermatotheca cannot be found. Although in that 
group the hermaphrodite gland usually takes the form of a 
layer spread over the liver, yet it is a separate mass (or 
masses) In Bathydoris, Alloiodoris, Doridoxa and 
Trevelyana. 
Doridoeides is thus an annectant form connecting the 
Holohepatica and Cladohepatica, but having the essential 
characters of the latter, and its systematic position can hardly 
be fixed without reference to our general ideas respecting 
the phylogeny of the Nudibranchiata. The most definite 
view respecting this phylogeny is that put forward by 
Pelseneer (‘Recherches sur divers Opisthobranches,’ 1894). 
According to it the Tritonide are allied to the Pleurobran- 
chide, especially Pleurobranchea. The Tritoniide are the 
common source of the Doridioidea and olidioidea, which 
