Fritillaria gracilis

Lohmann, 1896

Small sized species. The trunk is almost ovoid with the anterior third part broadened, pointened to the front. Mouth without lips.
The endostyle is short and moderately curved. There is no particular constellation of pharyngial glands. The testicle is sausage-shaped, curved along the rear and side wall of the posterior part of the body; at each end of the testes is an ovary mass. In old specimens, the testicles can become empty and therefore being invisible, whereas the ovocytes occupy entirely the both lateral parts of the trunk.
The tail has a narrow muscle band and tapers abruptly along the distal third part, ending in a rounded point. Glandular cells are visible in the tail fin.

Trunk length 0.5-0.8 mm, length of tail 2.4 mm.

Depth range

Distribution in the North Sea
All North Sea.

World distribution
Semi-cosmopolitan species from the Atlantic, Pacific and Indian Oceans (absent from sub-polar and polar waters); also present in the Mediterranean Sea, where it occurs predominantly from 50 to 150 m during summer and autumn.