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Show 402 DR. GWYN JEFFREYS ON MOLLUSCA OF THE [Apr. 16, triangular : skeleton or apophysary process in lower valve consisting of a simple loop, which is attached to the hinge by short and stout crura, ending in proportionally large triangular upright points or spurs, from which proceeds the obtusely angular or nearly semicircular portion of the loop at the base ; the outer surface of the crura is minutely and closely ridged across: inside furnished with about 10 ribs, but not with any intermediate striae ; edge notched to correspond with the furrows. L. 0*1, B. 0*085. 'Porcupine ' Exp., 1870 : St. 17«, 795 f. A single (upper) valve only. I have also, through the kindness of Professor Loven, a perfect specimen from the Josephine Bank off the Strait of Gibraltar, which was dredged in 340-430 fathoms. The peculiar shape and sculpture serve to distinguish this tiny species from the young of T. caput-serpentis, and from the next species T. trigona. 3. TEREBRATULA TRIGONA1, Jeffreys. (Plate XXII. fig 3.) S H E L L triangular, much compressed, solid for its size, semi-transparent between the ribs, and glossy: sculpture, 8 rounded longitudinal ribs, which radiate from the beak, and become gradually broader towards the front; those in the middle of each valve are the largest; the ribs are strongly wrinkled across by the lines of growth ; the interstices or furrows are narrow: ccecal tubuli numerous and close-set: colour clear white : margins gently curved and scalloped in front, abruptly sloping at the sides, broad or having somewhat ear-like expansions behind : beak short: foramen oval and proportionally large, incomplete: cleltidium small: hinge-plate thick: teeth in the upper valve short and strong: skeleton in the lower valve consisting of a semicircular loop, which is attached on each side by short and strong crura, and terminate in small pointed spurs: inside of both valves smooth and polished, exhibiting through the shell the thick outside ribs. L, 0*1, B. 0*1. A single living specimen was dredged by M r . Kent, in Mr. Marshall Hall's yacht the ' Noma,' off the coast of Portugal, in about 500 fathoms. He very obligingly gave it to m e with a specimen of the following species. It may perhaps be immature; but I cannot identify it with the young of any other species. This pretty little shell differs from the young of T. caput-serpen-tis in shape, colour, having fewer ribs and a smooth interior, and in the loop being rounded instead of incurved at the base. In T. caput-serpentis of the same size as this (Pl. XXII. fig. 1) the inside, especially in front, has strong and conspicuous ridges, which become notches in the full-grown shell. Typical. Loop short, semiannular. 4. TEREBRATULASUBQUADRATA2, Jeffreys. (Plate XXII. fig. 4.) S H E L L broadly triangular or oval, with a squarish outline; upper 1 Triangular. 2 Somewhat square. |
