76 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Zooecia having a chitinous frontal. Intertentacuiar organ present. Larva a 
Cyphonautes. No avicularia. No dietellae. Operculum with thickened border. 
Historical. — The family Electrinidae was established in 1851 by D’Orbigny for 
species possessing “ cellules en cornet,” and was based on the genus Electra Lamour- 
oux, 1816. Two genera, 
Canda and Caberea , which 
D’Orbigny included in the 
family at that time, had to 
be withdrawn, because they 
did not have the same larval 
features. The Electra pilosa 
group has been the subject 
of numerous anatomical 
studies. 
The Membranacea group 
is also a natural division, 
and it is considered as con- 
taining typical Membrani- 
pora , which is the basis of 
the family Membraniporidae 
Smitt, 1866. The inter- 
tentacular organ is known 
here also. In 1906 Miss 
Robertson discovered the 
Cyphonautes larva in Mem- 
branipora villosa , which 
therefore belongs to the 
same group. 
Electra and Membrani- 
pora , having similar larval 
forms, belong to the same 
family, Electrinidae. This 
name, given by D’Orbigny, 
has the right of priority. 
Classification. — The known genera of the Electrinidae are as follows: 
Electra Lamouroux, 1816. 
Membranipora Blainville, 1834. 
Heterooecium Hincks, 1892. 
Pyripora D’Orbigny, 1852. 
Herpetopora Lang, 1914. 
The two latter genera have been placed in the family on account of zooecial 
resemblance, and not from a study of their anatomy. 
Genus ELECTRA Lamouroux, 1816. 
1S16. Electra Lamouroux, Ilistoire des Polypiers Coralligenes flexibles, p. 121. 
The frontal is a gymnocyst. There is a circle of spines around the frontal area. 
The distal septulae are uniporous. The lateral walls have 2 or 3 multiporous 
septulae. 
i o' 
r opercular 
valve 
-(•areal spines ( 
®°oJ 
j-- gymnocyst 
V 
L-opesium j 
0 
° a 
© 
Gocl 
-flagellum 
"©1 4 
1 
f O 1 
0 1 
// ° °°°k 
1 °S/ 
// O / 
L 
c 
.*47 
Fig. 18. — Genus Electra Lamouroux, 1816. 
A-E. Electra pilosa Linnaeus, 1758. A. Several zooecia, X 46, 
illustrating structure. (After Hincks, 1880.) B. Drawing show- 
ing intertentacuiar organ (i. o.), X 20. C. Lateral wall, exhib- 
iting multiporous septulae (s), X 47. D, E. Uniporous septulae 
of the distal wall, X 47. (B-E, after Levinsen, 1894.) 
