NE.ERA. 53 



4. N. cuspida'ta*; Olivi. 



Tellina cuspidata, Olivi, Zool. Adr. p. 101, tab. iv. f. 3. N. cuspidatu, 

 F. & H. i. p. 195, pi. vii. f. 4-6, and (animal) pi. G-. f. 4-7. 



Body greyish or dirty white : mantle rather thin : tubes 

 nearly sessile, sometimes mottled with pink ; orifice of lower 

 one fringed ^dth 5 or 6 short cirri ; the base of each tube is 

 encircled by 6 rather long and slender filaments, which have 

 cup-shaped extremities, like the polypidoms of many zoophytes ; 

 these filaments occasionally are knotted or studded at intervals 

 with bulbs of an azure hue ; the orifice of the upper or excretal 

 tube is plain, but provided with the usual hyaline valve : foot 

 long, flexible, and white. 



Shell obliquely triangular (left valve sensibly larger than 

 the right), extremely gibbous and tumid, moderately solid, 

 opaque, and almost lustreless : sculpture, numerous slight and 

 irregular concentric striae or wrinkles, becoming closer and 

 flexuous towards the posterior side ; the upper angle on" that 

 side is crest-like and striated as in N. i^ostrata, but it is not 

 so distinctly defined, nor elongated to anything Hke the same 

 extent : colour whitish under the epidermis, which is light 

 chestnut or reddish-brown, thick (especially at the dorsal edges, 

 where it has somewhat the appearance of a ligament), some- 

 times coated with sand or mud : margins rounded on the an- 

 terior side as well as in front, with an abrupt and deep sinus 

 on the posterior side, which is somewhat twisted and compa- 

 ratively short, being about one -half of the entire breadth of 

 the shell ; posterior dorsal margin incurved ; anterior dorsal 

 margin forming a rounded slope, but not projecting as in the 

 last species : beaks inflected, and interlocking, or placed one 

 on each side instead of opposite ; umbones extremely promi- 

 nent ; dorsal excavation deep, heart-shaped on the anterior 

 side, and trench-like on the posterior : cartilage and ossicle as 

 in N. rostrata, but the former is horncolour, and the pit does 

 not project so far inwards : hinge-line obtusely angular : hinge- 

 plate thick : teeth, a strong recurved and rather short trian- 

 gular lateral in the right valve, and only an obscui-e and blunt 

 laminar lateral in the other valve : inside glossy, porcellanous, 

 and nacreous, indistinctly striated lengthwise ; it is furnished 

 on the posterior side in each valve with a thick rib, extending 

 from below the beak half-way across to the indentation that 



* Pointed. 



