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



profunda, lanceolata. • Umbones parvi, nivei, paulo prominentes, antrorsum versi. 

 Cardo dente unico conico iiifni apicem in valva dextra et 'duobus in sinistra instructa, et 

 margo posticus dorsalis valvas dextr^e dente laterali elongato, baud couspicuo munitus. 

 Ligamentum internum magnum, obliquum, in sulco infra marginem locatum. Pagina 

 interna baud nitida, subrugose radiatim striata, margine exteriori minute crenulato. 



Tbis species is tbin, ratber globose, about equiLateral, rounded, wbitisb, and, 

 judging from tbe single specimen under examination, somewbat tinted near tbe central 

 portion of tbe valves witb pale brown. It is sligbtly glossy, and sculptured witb fine 

 concentric lines of growtb and equally fine radiating strise, wbicb are almost obsolete 

 down eacb side and more or less indistinct near tbe middle of tbe valves, and entirely 

 absent near tbe umbones. Tbe anterior dorsal margin is oblique, and a little concave 

 by reason of tbe small, sbortly lanceolate and sligbtly sunken lunule. The beaks are 

 small, smootb, wbite, only a very little elevated, and curve over towards tbe front. 

 Tbe binge is composed of a single cardinal tooth in the right valve wbicb fits in between 

 two in the left, of which tbe anterior is tbe larger, and a narrow insignificant lateral in 

 tbe right, near but distinct from the posterior dorsal edge, which is received by a 

 corresponding groove in the other valve. Tbe ligament is rather large, entirely internal, 

 and placed in an oblique furrow, extending from the apex not c|uite to the end of tbe 

 lateral teeth. The interior has very little gloss, and is rather strongly radiately striated 

 and marked with numerous shallow punctures, neither being met with beyond the 

 pallial line. The muscular scars are large, and the inner margin of tbe valves minutely 

 crenulated. 



Length 9^ mm., height 9, diameter 6f. 



Habitat. — Port Jackson, New South Wales, in 6 to 1 5 fathoms. 



This species is larger than Lucina parvula, Gould, also found at this locality, 

 more finely radiately sculptured, and has the inner edge of the valves more delicately 

 notched. 



Lucina [Loripes?) gordoni, n. sp. (PI. XIII. figs. 12-1 2a). 



Testa j)arva, modice convexa, rotundata, sequilateralis, alba, lineis increment! 

 tenuibus elevatus striisque radiantibus obsoletis sculpta : margo dorsi anticus leviter 

 obliquus, parum excavatus, posticus rectiusculus, horizontalis. Latus anticum regu- 

 lariter arcuatum, posticum obtusius. Umbones parvi, acuti, paulo prominentes. 

 Dentes cardinis in valva sinistra duo divergentes insequales, antico majori ; margo 

 posticus dente laterali parvo instructus. Ligamentum internum angustum, in sulco 

 profundo obbquo situm. Pagina interna baud nitida, plus minusve radiatim substriata, 

 margine minute crenulato circumdata. 



