374 On new Deep-sea Mul/usca. 



dextra dente unico lateral! acuto postice instructus ; fossa liga- 

 menti parva, postice inclinata. 

 Longit. 15 millim., alt. 11, diam. 9^. 



Hah. Off Andaman Islands, lat. N. 11° 25' 6", long. E. 

 92° 47' 6", in 405 fathoms. 



Closely allied to C. cuspidata, Olivi, but slightly different 

 in form and having a few radiating lines posteriorly. 



jMyonera hicarinata. 



Testa sequivalvis, inajquilateralis, postice hians et breviter rostrata, 

 antice rotundata, alba, tenuis ; valvae tenues, inflatse, carinis 

 duobus acutis radiantibus post medium instractae, ante cariuam 

 anteriorem concentrice subdistanter costulatse, pone carinam 

 lajves, liueis incremeiiti tenuissimis striatse ; umbones promi- 

 nentes, incur%-ati ; margo dorsi utrinque declivis, ventris antice 

 arcuatus, post et inter carinas excavatus ; cardo edentulus ; liga- 

 mentum internum in fossa angusta in utraque valva situm, 

 ossiculo teiiui firmatura. 



Longit. 14 millim., alt. 11, diam. P. 



Hah. West of Malabar coast, lat. N. 13° 47' 49", long. E. 

 7a° 07' 0", in 636 fathoms. 



A very beautiful species, readily distinguishable by its 

 remarkable sculpture. The concentric costai on the anterior 

 half of the valves are finer and closer together towards the 

 umbo than towards the ventral margin ; they do not extend 

 quite to the submedian keel, and become finely attenuated 

 anteriorly. 



Lyonsia j ucunda. 



Testa tenuis, fragiHs, oblonga, antice rotundata, postice subtruucata, 

 a?quivalvis, infequilateralis, alba, radiatim carinata, carinis duobus 

 pott medium aliis majoribns, omnibus spinulosis vel tuberculatis, 

 undique minute granulata ; margo dorsi anticus rectiusculus, 

 valde declivis, posticus longior, minus obliquus, leviter concavus, 

 ventralis inter carinis sinuatus : cardo edentulus ; ligamentum 

 internum ossiculo parvo munitum ; pagiua interna subnacrea, 

 radiatim sulcata, sulcis punctatis. 



Loiigit. 12| millim., alt. 8, diam. 6. 



Ilah. N. Sentinel, bearing N. 15° W. 18 miles, 250 fathoms. 



Crijptodon inventigatoris^ Smitli. 



Ciijptodon invedigatoris, Smith, Ann. & Mag. Nat. Hist. 1895, vol. xvi. 

 p. 13, pi. ii. figs. 6, 6 a. 



Ilah. Off west coast of Ceylon, lat. N. 8° 35' 45", long. E. 

 81° 17' 45", in 609 fathoms. 



