331 
NOTES ON SOME NEW OR LITTLE-KNOWN MEMBERS OF THE 
FAMILY DORIDIIDZ.! 
By Sir C. N. E. Extor, K.C.M.G., 
H.M. Commissioner for the East Africa Protectorate. 
Read 3rd April, 1903. 
PLATE XIII. 
In the following paper I propose to describe some new or little-known 
members of the family Doridiide, captured on the east coast of Africa 
and at Rotuma in the South Pacific. The specimens from the latter 
locality were kindly lent me by Mr. Stanley Gardiner. 
The Doridiidee are Tectibranchia of the subdivision Cephalaspidea, 
bearing two dorsal shields with a furrow between them. ‘The anterior 
shield has free margins, but as a rule is not developed into tentacles ; 
the posterior has the margins less deyeloped, but is produced behind 
into two processes. The foot is broad, truncate before and behind, 
and continued on each side into a fairly ample parapodium, from which 
it is not clearly divided. The parapodia are united behind, and the 
posterior part of the body hangs over or rests on them. Organs 
analogous to rhinophores are often present in the form of lamelle 
under the sides of the head-shield or lumps with bristles around the 
mouth. The branchia is a large bipinnate plume, posterior and on the 
right side. Behind it is the vent, in front of it the genital orifice, 
which is connected by an open groove with the verge on the right 
anterior extremity of the body. ‘The verge is grooved, the prostate 
double or single. The shell is wholly internal, posterior, and generally 
composed of a minute spire with a single solute whorl; sometimes 
wholly membranous, sometimes partly calcified, rarely wholly calcified. 
There are no jaws, radula, or stomach plates, but there is, as a rule, 
a large, sometimes colossal, buccal bulb with thick muscular walls. 
This, however, is not the case in some of the species here described. 
Since, however, they are in other respects typical Doridia, and the 
difference in the digestive tract is one of development, not of structure, 
it is not necessary to create a new genus for them. 
Three genera are recognized—Doridium? (Meckel), which has no 
tentacular appendages to the anterior shield and short posterior 
processes ; Chelidonura (Adams), also without tentacular appendages, 
' See R. Brren, ‘‘ Die Gruppe der Doridiiden,’’ Mittheil. Zool. Station Neapel, 
xi (1893), pp. 107-135: ib., ‘* Reports on the dredging . . . carried on by the 
. . . Albatross, xiii, Die Opisthobranchien,’’ Bull. Mus. Comp. Zool. Harvard 
Coll., xxv, No. 10 (1894), pp. 125-233: ib. in Semper’s ‘‘ Reisen im Archipel 
der Philippinen, Wissensch. Result.,’’ Bd. vir, abth. iv, absch. 2, lief. 1 (1900), 
p- 177, and absch. 3, lief. 2 (1901), p. 302: ib., ‘‘ Reise nach dem Pacific 
(Schauinsland). Die Opisthobranchier,’’ Zoo]. Jahrb., xiii, Syst. (1900), p. 211. 
? Pilsbry prefers the older name Aglaja for Doridium. 
