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



This species ranges further north as far as the West Indies. Specimens from the 

 Island of St. Thomas in tlie British Museum are perhaps a trifle longer in proportion to 

 their height than the examples from Monte Video. The largest of the Caribbean shells is 

 29 mm. long, IG high, and 8 in diameter. 



Tellina [Macoma) arafiirensis, n. sp. (PI. IV. figs. 6-6?>). 



Testa transversim oblonga, antice rotundata, postice angustata, truncata, modice 

 convexa, valde insequilateralis, alba, paulo iridescens, epidermide tenui flavo-grisea partim 

 induta, lineis incrementi concentricis, striisque tenuissimis radiantibus insculpta. Valvse 

 jjostice prope marginem dorsalem sulco inconspicuo decurrente signatse, aliquantoque 

 hiantffi. Margo dorsi anticus elongatus, parum obliquus, leviter arcuatus, posticus valde 

 declivis, rectilinearis. Ventris margo antice arcuatus, latus posticum versus inconspicue 

 subsinuatus vel incurvatus. Area lanceolata, profunda, marginibus subacutis inclusa. 

 Dentes cardinales parvi, in valva dextra duo, posticus valde fissus, in sinistra unicus, 

 erectus. Pallii sinus magnus, subquadratus, fere ut in Tellina truncata, Jonas. 



Length 47 mm., height 30, diameter 14. 



jfZct5?'to/.— Station 190, Arafura Sea, in 49 fathoms; green mud. 



This species is somewhat intermediate in its characters between Tellina galatcea, 

 Lamarck, and Tellina truncata, Jonas. It is not quite so elongate as the former, but 

 rather more prolonged than the latter. It differs from Tellina galatcea also in sculpture, 

 being less coarsely radiately striated, not granular, lacking the peculiarly sculptured rays, 

 and it is also faintly iridescent. The posterior side of lellina arafurensis ends in a 

 narrower truncation, and the dorsal slojie is rather more abruptly descending, yet not so 

 suddenly oblique as in Tellina truncata. The latter is decidedly higher, and the hinder 

 dorsal margin or ligamental slope being more abruptly oblique, the apical or umbonal 

 angle is more acute than in the present species. Tellina guhernaculioji, Hanley, said to 

 liave been found on the west coast of Central America, is also very closely allied to the 

 species under consideration. It has a broader truncated end posteriorly, and a shorter 

 ligamental margin than Tellina arafurensis. 



Tellina murrayi, n. sp. (PL III. figs. 8-86). 



Testa transversa, elongata, tenuis, paulo ina3C[uilateralis, albida, versus umbones 

 pallide flavescens, semipellucida, liris tenuibus concentricis aliisc^ue confertioribus 

 radiantibus minus conspicuis concinne ornata. Margo dorsi utrinque leviter sequaliterque 

 declivis, antice vix convexus, postice primo paulo concuvus. Margo ventralis late cur- 

 vatus, latum posticum subrostratum versus subsinuatus, antice adscendens, rotundatim in 



