104 JOURNAL OP 4 CONCHOLOGY, VOL. 9, NO. 4, OCTOBER, 1898. ; 



but it differs from the more orbicular P. patagonicus King, in the 

 camparatively greater height of the shell, crenulated ribs, and un- 

 equal ears. 



Mytilus bifurcatus Gonr. — A peculiar looking shell, about 25 

 mm. in length, strongly grooved, triangularly ovate, very gibbous, 

 and of a dark indigo blue-black colour. Reeve does not give any 

 locality, but it is recorded from California by Paetel. 



M. magellanicus Chemn. — Three young and two adult examples 

 of this fine pear-shaped shell. It is blue-black in colour, with waved 

 crenated ribs. The larger shells bear beautiful growths of Bryozoa, etc. 



M. ungulatus L. — With the exception of size, there seems little 

 to separate this from our Mytilus edulis. It seems to run through the 

 same gradations of form, including typical var. gallo-provincialis Lm. 

 Recorded from Chili (Cuming). Paetel makes M. ungulatus synony- 

 mous with M. laius Lm. from New Zealand, but this can scarcely 

 be correct. 



Modiolarca pusilla A. Gd. — One typical example. Recorded 

 from Kerguelen (Fischer). 



M. trapezina Lm. — Nine specimens, in various stages of growth, 

 of a very elegant shell, varying in colour from bright orange to pur- 

 plish yellow or rich sienna-brown. Recorded from Strait of Magellan 

 (Paetel) ; Kerguelen and Auckland (Fischer). 



Cyamium falklandicum sp. n. (PI. L, fig. 12). 



C. testa mcdiocri, tzquivalvi, incequilaterali, oblongo-rhomboidali, 

 tenia, albida; valvis sub lente undique con cent rice striatis, striis rudibus, 

 posticum apud marginem rugoso-laminatis, umbonibus prominulis, 

 contiguis; valvis dorsaliter postic'e leniter declivibus, prolongatis, antice 

 rotundatis, Ugamento corneo, externo, valvam apud rectam dente car- 

 dinali magno, bifido, apud sinistram duobus minoribus; superficie interna 

 alba, parum nitente, linea palliali indistincta, paullum sinuosa. Alt. 7, 

 lat. 12, diam. 4 ;/////. 



This interesting addition to a very circumscribed genus has been 

 confused with C. antarcticum Phil., by Gwyn Jeffreys. 1 This latter, 

 however, is quite distinct, and correctly-named examples exist in 

 the British Museum, where also is this species without a name. 

 It is smallish in size, equivalve, very inequilateral, rhomboidal, 

 thin, white, the valves concentrically striate, and towards the pos- 

 terior margin wrinkled-laminate ; the ligament is horny and ex- 

 ternal, the posterior dorsal margin gradually sloping, prolonged, 

 anteriorly rounded, the cardinal tooth in the right valve is large and 

 bifid, in the left there are two smaller teeth ; within the surface is 



1 Brit. Conch., vol. 2, p. 257. 



