OPHIUROIDEA 245 



off Plymouth, round the Irish coasts to the north, and as far south 

 as Dogger Bank along the North Sea coasts ; also recorded from 

 the Lousy Bank. In the area N. and W. of Shetland it is very 

 numerous, and, together with Echinocyamus pusillus, char- 

 acterises the animal community living there. It is elsewhere 

 distributed from West Finmark to the Sound in the Scandinavian 

 seas. It has also been recorded from the Bay of Biscay and the 

 Mediterranean ; but as it has previously been erroneously 

 identified with Ophiura Grubei Heller, these statements are not 

 reliable. Also the statement of its occurrence at the east coast 



Fig. 133. — Ophiopluteus, probably of O. affinis. The larva is about to 

 metamorphose, the young brittle -star being already distinct, x ca. 50. 

 (From Danmark's Fauna.) 



of N. America is scarcely beyond doubt (see the following species). 

 Bathymetrical distribution ca. 8-550 m. 



O. affinis, together with the following species, recalls in several 

 features the genus Ophiocten, and perhaps ought rather to be 

 referred to that genus. Anyhow, it stands apart from the other 

 species of Oj)hiura, especially through the second pore pair not 

 opening into the mouth slit. 



8. Ophiura signata (Verrill). 

 (Syn. Ophioglypha signata Verrill.) 



Very closely resembling 0. affinis, the only noteworthy differ- 

 ence being found in the shape of the mouth shields, which are in 

 O. signata scarcely longer than broad, and scarcely reach half 

 way to the edge of the disk. It may perhaps be questionable 

 whether it can be maintained as a species separate from affinis. 



In British seas 0. signata has been found in the Faroe 

 Channel, cold and warm area, and in considerable numbers off 

 the west coast of Ireland, where it is stated to be one of the most 

 characteristic species of the mud and ooze between ca. 500-900 m. 

 Elsewhere recorded only from off the N. American east coast. 

 Bathymetrical distribution ca. 110-900 m. 



