Boone, Mollusca, Cruises of "Ara" and "Alva" 323 



Order: EULAMELLIBRANCHIA 



Family: LIMIDAE 



Genus: LIMA Cuvier 



Subgenus: Limaria 



Lima (Limaria) fragilis (Gmelin) 



■f 



Plates 134 and 135 



Type : Gmelin's type locality is listed as rare in the Nicobar 

 Islands. The type is deposited in the museum at Upsala. 



Distribution: This species has a bathymetric occurrence 

 ranging from the littoral zone to 57 meters and is widely distrib- 

 uted in the Indo-Pacific, being known from Mauritius (Martens) 

 eastward in the Nicobar Islands (Gmelin) ; at 16 "Siboga" sta- 

 tions in the Dutch East Indies and Sulu Archipelago (Prashad) ; 

 Torres Straits (Jukes) ; Port Essington (E. A. Smith) ; Port 

 Molle, Queensland (Coppinger) ; Queensland coast (Hedley) ; 

 Palm Islands, Queensland (Boone), and eastward in the Fiji 

 Archipelago, at Oomaga Reef (E. A. Smith), and Tahiti (Sow- 

 erby) . 



Material examined: Eight specimens, (seven and one-half 

 bivalves), taken on the reef. Falcon Island, Palm Islands, Queens- 

 land, Australia, October 7, 1931. 



Technical description : The eight specimens of this delicate- 

 ly beautiful shell are typical representatives of Lima fragilis. The 

 shell is equivalve, but little elongated, thin, with the hinge area 

 narrow, the resilium nearly straight dorsally ; the auricles small, 

 the anterior one obtuse, the posterior acute. The shell is widely 

 gaping on both sides, the margin of the posterior hiatus being 

 formed by an internal rib. The umbo is small, prominent, some- 

 what conic, the adjacent and median region being nearly smooth 

 except for a faint impress of the radiating costae ; the dorsal sur- 

 face with about 28 hollow, thread-like ridges that extend to the 

 margin, making the latter slightly dentate or crenulate. Fine con- 

 centric lines of growth also pattern the surface, these being 

 stronger near the margin, where they not infrequently retain a 

 granulate appearance, due to these crenulate old marginal lines. 



