284 THE VOYAGE OF H.M.S. CHALLENGER. 



principal ribs at rather equal distances, the first forming the straightish dorsal line. In 

 addition, towards the umbones, there is a slighter ridge in each space between the large 

 ribs which soon becomes obsolete. Also near the ventral margin there are four or five 

 obsolete ridges, which are chiefly indicated by that number of rows of moderately 

 distant small scales. The scales on the principal costse are very large, rather tubular and 

 elevated. 



Family A v i c u l i d .-e. 

 Malleus, Lamarck. 



Malleus alhus, Lamarck. 



Malle^is alhus, Lamarck, Anim. sans vert., ed. 2, vol. vii. p. 91. 

 Malleus alhus. Reeve, Conch. Icon., vol. xi. pi. i. fig. 1. 

 Malleus alhus, Chenu, ilan. Conch., vol. ii. fig. 81.5. 



Habitat. — Cape York, in 3 to 12 fathoms. 



This well-known shell has been recorded from Japan, China, and Pliilippine Islands, 

 and probably has a still wdder distribution in eastern seas. 



Avicula (Klein), Bruguiere. 

 A'vicula macro2')tera, Lamarck. 



Avicula macroptera, Lamarck, Anim. sans vert., ed. 2, vol. \n. p. 97. 

 Avicula macroptera. Reeve, Conch. Icon., vol. x. pi. iL fig. 2. 

 Avicula macroptera, Dunker, Conch.-Cab., ed. 2, p. 22, pL vii. 



Habitat. — Station 186, off" Cape York, North Australia, in 8 fathoms; coral mud. 

 This large species is also said to have been obtained at the Moluccas. 

 Avicula {3Ieleagrina) muricata, Reeve. 



Avicula muricata. Reeve, Conch. Icon., vol. x. \>\. vi. fig. 12. 



Avicula {Mcleagrina) muricata, Dunker, Conch.-Cab., ed. 2, p. 47, pi. xvi. fig. 2. 



Habitat. — Station 187, near Cape York, North Australia, in 6 fathoms ; coral mud. 



All the Challenger specimens of this species are young shells. Reeve's figure was 

 taken from a specimen which was to some extent Ijroken on the posterior side, so that 

 the sinus at the upper part appears too deep. A feature worth remarking is the fine 

 radiate ridges on the anterior auricle. 



Avicula {Meleagrinct) sqiiamidosa, Lamarck. 



Avicula squamulosa, Lamarck, Anim. sans vert., ed. 2, vol. vii. p. 100. 



Avicula squamulosa, d'Orbiguy, Voy. dans TAmor. Mdrid., p. 658. 



Avicula squamulosa, d'Orbigny, in Sagra's Hist. Cuba, Mollusques, vol. ii. p. 342. 



Habitat. — Station 36, off" Bermuda, in 30 fathoms ; coral. 



