MOLLUSCA. 
503 
Anochnta strebelti, sp. ii., Lea, 1. c. p. 160, Vera Cruz. 
Anodonia hridtjcsii^ inaiquivalviSf jeioettiand, lenticnlaris^ and granadenm^ 
8pp. nil., all from Tjako Nicaragua. Lea, 1. c. pp. 06, 90. 
Anodonia gigantea (Spix), .4. exotica (ham.), A. latimarginata (Lea) = ?;?«- 
tagonica (Lam.), and A. tenehricosa (Lea) described from Soutb-Brazilian 
specimens and compared with several other allied species by Martens, Mai. 
Bliitt. XV. pp. 190-201 & 217. The South-American species are distributed 
in four groups, — rotundatfe, latimarginatse, angulatse, and ensiformes, 
pp. 210, 211. — Five species from South America are figured in Sowerby’s 
Continuation of Reeve’s Conch. Ic. 
Leila castelnaiidii (Hupe) described from specimens from the Jacuhy River 
in Southern Brazil, by Martens, 1. c. pp. 201, 202. 
Mycetopus (Orb.). This genus is treated of in Sowerby’s continuation of 
Reeve’s Conchologia Iconica, parts 209, 270, & 272, and illustrated by four 
plates. — M. plicatus, sp. n.. Sow. 1. c., Victoria River, Australia; M. subsinu- 
atus, sp. n.. Sow. l.c., New Granada.—Mycetopus falcatus, sp. n., Higgins, 
Rroc. Zool. Soc. 1808, p. 179, pi. 14. fig. 0, Chyavetas, Upper Amazons. 
[Similar to the Siamese M. emarginatm, Lea.J 
Solenaia, g. n., for Mycetopus emarginatus (Lea). Conrad, Am. Journ. 
Conch, iv. p. 249. 
Iridina. This genus is treated in Sowerby’s continuation of Reeve’s Con- 
chologia Iconica, parts 208, 269, with two plates. — I. angustata, sp. n. 
[ Spatha] Iridina nibens from the Niger is not to be distinguished specifi- 
cally from that of the Nile. — I. wclwitschii, sp. n.. River Muria, Angola. 
Morelet, Moll. Terr, et Fluv. Voy. Welwitsch, pp. 98, 99. [The latter is 
analogous to Sp. arcuata (F^r.) from the upper Nile.]* 
.^TIIERIIDJE. 
JEtlicria plumhca (F^r.) = transversa and semilunata (Lam.) = carteroni 
(Michelin), River Lucala, Angola. Morelet, 1. c. p. 100. 
MyTILIDtE. 
Mytilus d'assitesta, sp. n., Lischke, Mai. Blatt. xv. p. 221, Japan ; allied to 
giganteus (Holmberg), which occurs also in Japan. 
Mytilus exustus (L.) = domingensis (Lam. ?, Orb.), from Montevideo, com- 
pared with M. darwinianus (Orb.). Martens, Mai. Blatt. xv. p. 206. 
Modiola antarctica, sp. n., Philippi, Mai. Blatt. xv. p. 224, Straits of Ma- 
gellan ; resembling young specimens of M. barbata (L.). 
Dreissenidae. 
Dreissena yolymorpha (Pall. ). See Acclimatization, p. 443. G assies observed 
that the animal voluntarily breaks the threads by which it has attached itself, 
and creeps about by stretching and shortening its foot, somewhat like a leech. 
Journ. Conch, xvi. pp. 24-27. 
Aviculid;e. 
Vulsella and Crenatida. The characters of the mantle, the bisymmetrical 
structure of the ligament, and the development of the elongated foot without 
byssus are essentially the same in both genera. Vulsella approaches nearer to 
