LAMELLIBRANCHIATA. 59 



BARNEA. 



Shell ovato-obloug ; gaping anteriorly ; a single lanceolate dorsal 

 accessory piece ; hinge margin reflected. 



1. B. Similis, Gray, Die/. N.Z., ii., p. 254. Eather elongate, 

 acute in front, tapering behind ; with concentric lauiinse which are 

 higher and closer together at the anterior end, where they are crossed 

 by radiating lines, sub-spinose at the crossings ; dorsal plate elongate, 

 acute in front, truncated behind. Height, 1 ; length, 2'5. 



Common. 



PHOLADIDEA. 



Siphons with horny or shelly pieces at their base ; shell widely 

 gaping in front, but closed by a callous plate ; two dorsal pieces, 

 straight. 



Britain. Ecuador. 



2. P. tridens, Gray, Dieff. N.Z., ii.,p. 254. Ovate, with a deep 

 central groove ; front half with close waved concentric ridges ; hinder 

 half with distant regular concentric grooves ; front gape ovate, at 

 length closed up, the two hinder processes forming together a cup 

 about as long as broad, each furnished with a sub-marginal and central 

 rib. Height, 75 ; length, T5. 



TEREDO. 



Shell globose, gaping anteriorly and behind ; valves trilobate, 

 divided by a single transverse groove ; hinge margins inflexed an- 

 teriorly ; interior of valves furnished with a long curved process. 

 Living at the inner extremity of a burrow, partly or entirely lined 

 with shell. 



All seas, 



3. T. antarctica, sp. nov. Shell globose, the valves trilobed, 

 ear-shaped behind, lower lobe produced, acute, the interior process for 

 attachment of the pedal muscle dilated at the end ; anterior end deeply 

 notched, the notch forming a right angle ; outside smooth behind, 

 striated in front by lines parallel to the edge of the notch, the striae 

 on the lower and posterior part being finer than those on the upper 

 and anterior part, and the interstices with minute cross striae, while 

 the interstices of the upper striae are smooth ; tube and valves ? 



Auckland. 



FAMILY GASTEO CH JEJSTID^: . 



Shell equivalve, gaping ; valves thin, edentulous, united by a liga- 

 ment, sometimes cemented to a shelly tube when adult ; adductor 

 impressions two, pallial line sinuated. 



ASPERGILLUM. 



Shell small, cemented to the lower end of a shelly tube, the urn- 

 bones alone visible externally ; tube elongated, closed below by a per- 



