482 ON THE FAUNA AND BOTTOM-DEPOSITS NEAR THE 30-FM. LINE 



certainly referable to this species, were also taken on the Bolt Head 



Shell (Jravel (XVII). 



DisTiiinuTiON', Channel, Atlantic, Mediterranean (fide Saint- Joseph, No. 102). The 

 Caudan dredged one specimen in the Bay of Biscay on mml in 98 fatlioms (Ronle, No. 101). 

 Saint-Joseph states that it occurs on all French Coasts on nuuldy sand. 



Chaetopterus variopedatus. (Following Joyeux-Laffuie, No. 65, and 

 Saint- Joseph, one species of Chnetopterus only is recognised as inhabit- 

 ing European Seas.) Chart X. The most striking feature of the coarse 

 gravel grounds in the neighbourhood of the Eddystone is the abundance 

 of Chadoptcms, and the presence of large masses of its leathery tubes 

 has a great influence on the general fauna of the grounds. The species 

 is most abundant on the coarse gravel and sand of Grounds IX. and XL 

 and on the fine gravel of Ground XIV. to the westward of the Eddy- 

 stone, and on the gravel and mud of Ground XIII. to the south-east. 

 Eroni these centres of distribution it extends in diminishing numbers on 

 to the surrounding grounds. On the fine sand of Ground VII., where 

 shells are numerous, Ghaetopterus is still moderately plentiful, and a 

 good many were even present on the fine sand of Ground VI., still 

 further from the centre of distribution. On other fine sand grounds, as 

 well as on the Bolt Head Shell Gravel and the Prawle Stony Ground, 

 the species is either absent or represented only by one or two stray 

 tubes. 



Hahits. The tubes of Chaetopterus are generally attached in the first 

 instance to shells, but they soon attain a size very much greater than 

 that of the shell to which they originally fixed, and they then attach 

 themselves to the gravel itself or to any solid object with which they 

 come in contact. In this way one often finds large clusters of the tubes 

 joined together into masses, with two or three shells fixed firmly to the 

 mass. The fauna which depends directly upon the presence of these 

 masses of tubes has already been described (see p. 414). In addition to 

 the species there mentioned the Polyzoan IfypoplioreUa cxpansa, Ehlers, 

 has been found in Chuctopterus tubes taken in the neighbourhood of 

 the Eddystone (Harmer, No. 37), and was probably present in a large 

 proportion of the specimens captured (compare also Joyeux-Laffuie, 

 No. 64). The habits of Chaetopterus are well described by Joyeux- 

 Laffuie (No. 65). The animal obtains its food by drawing a current of 

 water through its tube and extracting the floating organisms. 



Dl.STiMBUTioN. Geographical. North('rn Seas, Channel, Atlantic, Mediterranean [fide 

 Saint-Joseph, No. 102]. 



Depth and Botlom-deposil. Joyeu.x-Laffuie (No. 65) states that on thu French coasts 

 Chaetopterus is found in shallow water and even occasionally between tide-marks in 

 sheltered situations, where the action of the waves is slight, but that on exposed coasts 

 it occurs only in dce])er water. It is often washed ashore in very large numbers after heavy 

 gales. Saint-Joseph (No. 102) found it at Dinard on the shore only. In the Irish Sea it 

 is recorded from the shore at low-water at Beaumaris (Williams, fide Hornell, No. 49), on a 



