370 Bulletin American Museum of Natural History [Vol. LIII 
In Iphigenta rostrata a siphonal cavity within the mantle is parti- 
tioned off, as in Cyrenidz and many other groups. The siphons are long 
(8 mm. in their contracted state), equal, wholly free, both papillose at 
the orifices, and externally they are marked with widely spaced longi- 
tudinal threads, as figured by Rang for Egerza,! but weaker. The mantle 
has a double line of papille just within the edge, the outer papille minute, 
the inner rather long; at a distance of about 2 mm. within the row 
of papille there is a narrow, smooth ridge parallel with it. It is nowhere 
concrescent except at the partition mentioned, which does not reach the 
edge- The gillsare free throughout. The labial palpi are quite long. 
In dried specimens of /. congo, which were soaked, all of the same char- 
acters were observed, except that the mantle has a single row of papille. 
As I. congo is closely related to Fischerta delessertit Bernardi, and 
I. rostrata stands very near I. levigata (Gmelin), the type of Iphigenia, 
it appears that these two supposed genera are to be united. If Profischeria 
is retained at all, it could be used as a section for the small, strongly 
violaceous, more fluviatile forms; but in all structural characters of 
shell and animal they appear to agree fully with the large, more whitish 
I. rostrata. 
While this group is similar to Egeria in essential characters, it differs 
by the thinner shell with narrow hinge-plate, longer lateral teeth and 
especially by the very much larger pallial sinus, extending beyond the 
middle of the valve. No species of intermediate character have been 
found; and we agree with most authors who have dealt with the group 
in ranking it as a genus distinct from Egeria. 
Iphigenia is known from the coast. and the rivers of West Africa and 
from the Pacific and Atlantic coast of Central and South America. In 
West Africa the fluviatile species occur from Senegal to the Congo 
estuary, but, curiously enough, have not been reported from Angola. 
They are found from far in the interior (I. centralis in the middle Niger) 
to strongly saline waters, associated with Tellina, Corbicula, etc. 
Iphigenia approximans (Preston) =Fischeria approximans Preston, 1909, 
Ann. Mag. Nat. Hist., (8) ITI, p. 186, Pl. vit, fig. 18. Podor, Senegal River. 
| Iphigena centralis (Germain) = Fischeria centralis GERMAIN, 1904, Bull. Mus. 
Hist. Nat. Paris, p. 471; 1908, in A. Chevalier, ‘L’ Afrique Centrale Francaise,’ p. 
582, Lithogr. Pl., figs. 6 and 7. Middle Niger and Bani. 
Iphigenia congo Pilsbry and Bequaert. See p. 373. 
Iphigenia curta (Dunker). See p. 371. 
Iphigenia delessertit (Bernardi) = Fischeria delessertit BERNARDI, 1860, ‘Monogr. 
Galatea et Fischeria’ p. 46, Pl. 111, figs. 3and 4.and Pl. rx, fig. 5. River near Cape Palmas. 
11832, Ann. Se. Nat., XX’V, PI. v, figs. 1-3. Also in Bernardi, 1860, ‘Monogr. Galatea et Fischeria,’ 
anatomical Plate. 
