ACEPHALA. 403 
PsaMMoBIA FLORIDA (Gould). 
Testa transversa, oblonga, tenera, polita, purpurascens, posticé albo-ra- 
diata ; limbo epidermide flavo-virescente induto ; natibus postmedianis, 
inconspicurs ; latere antico semi-elliptico, apice supra-mediano ; latere 
siphonali angustato, acute rotundato, apice infra-mediano ; margine 
ventrali rectiusculo: interior incarnata ; sinu siphonali angusto, pre- 
longo ; cardine dentibus duobus minutis divaricantibus in utraque 
valva instructo. 
Psammobia florida, Gouin; Proceed. Boston Soc. Nat. Hist., in. 
254. June 1850. Expedition Shells, 81. 
SHELL delicate, fragile, lucid, transversely oblong-oval, somewhat 
rhomboidal, very inequilateral, smooth and shining. Beaks delicate, 
at the posterior third; anterior end obliquely rounded, acutely above, 
less so below, tip above the middle; posterior end subtriangular, tip 
acutely rounded, below the middle ; dorsal and ventral edges anteriorly 
parallel, posterior dorsal edge rapidly declining, angular. Valves 
slightly convex; epidermis shining, zoned indistinctly with livid flesh- 
colour and yellowish horn-colour, with two or three pale rays poste- 
riorly ; ligament elevated, short, pale chestnut. Interior livid brown ; 
siphonal sinus narrow, extending two-thirds across the shell; muscu- 
lar impressions distinct. Hinge with two minute, approximate, di- 
verging teeth in each valve. 
Length an inch and a quarter; height seven-tenths of an inch. 
Inhabits Illawarra, New South Wales. Drayton. 
A shell closely resembling in structure and exterior colouring 
Machera costata. It has the form of P. vespertina, except that the 
beaks are removed much farther backwards. 
Figures 513, 513, lateral and dorsal views of the shell; 5134, the 
hinge. 
