39 



ON THREE NEW SPECIES OF SHELLS FROM DEEP-SEA 

 DREDGINGS IN THE INDIAN OCEAN. 



By G. B. SowEKBT, r.L.S., etc. 



Bead Novouber IQth, 1893. 



Yerticoedia optima, n.sp. PL V. Fig. 3. 



Testa sub-ovalis, inflata, ajquivalvis, insequilateralis, alba, minii- 

 tissime granulosa, radiatim multilirata, liris eximie squamo-spinosis. 

 Margo dorsi anticiis prope umbones levitcr incurvus, deinde arcuatus, 

 posticus oblique rectiusculus. Margo ventralis rotunde arcuatus. 

 Latus posticus obtuse biangulatus. Umbones prominentcs, antice 

 leviter incurvati, ad apicem acutiusculi, aliquanto ante medium siti. 

 Lunula excavata, longiuscula. Dens cardinalis valvoe dextrse prominens, 

 mediocriter raagnus, crassus acutiusculus, leviter curvatus. Fossa 

 ligamenti obliqua, breviuscula, mediocriter lata. Lamina postica 

 longiuscula paulo elevata. Lamina cardinalis valva3 sinistra) promi- 

 nens, arcuata. Pagina interna argentea obsolete radiatim substriata, 

 ad marginem crenulata. XJmbono-marg. 29, antero-post. 35 mm. 

 Sal. — Indian Ocean, off Port Blair, Andaman Islands, 188 fathoms. 



The genus Verticordia is to be seen in but few collections of recent 

 shells. Ten have been described as species, but of these some are 

 synonyms : for instance, V. Japonica, A, Adams, is identical with 

 V. Deshayesiana, Pischer, and probably some of the smaller forms 

 which have been separated will have to be united. It is also probable 

 that some are undeveloped shells. The largest species hitherto re- 

 corded, V. tornata, Jeff., does not measure more than about 12 mm., 

 V. Beshayesiana coming next, the others being mostly very minute.^ 



The splendid species I have now the pleasure of describing is 

 1 f inch in width, so that leaves all others far behind in the matter of 

 size. It is of a rounded, inflated form, the whole surface is minutely 

 granular, and the numerous radiating liroe are covered with short 

 erect spines. The interior is of beautiful silvery pearl, with muscular 

 scars scarcely visible. The generic character indicated by the hinge 

 is very decided, the single tooth in the right valve being thick and 

 prominent. 



This unique specimen is now in the collection of Mr. James J. 

 MacAndrew. 



^ Since writing the above, my attention has been drawn to the description 

 by Dall of a larger species (which by an oversight has been omitted from the 

 Zoological Record), under the name of, Verticordia elegantissima (Bull. Mus. C. L. 

 vol. ix. p. 106). A single valve of this is mentioned, measuring 30 x 23 mm. 



