32 SABELLARIA ALVEOLATA. 



been fixed the annelid by a to-and-fro motion appeared to rub the inner surface of the 

 tube with the region just below the palps, where it is probable glands for secreting the 

 lining of the tube may exist. He has studied the building organ in a young specimen 

 2 mm. in length (Fig. 138, p. 27), and two main apertures are present, one at each side 

 of the organ. 



Mr. Watson also noticed in a young example the ejecta discharged from the gut 

 in a thread-like form, and worked forward by ciliary action and perhaps the movement 

 of the bristles. The annelid then protruded its anterior region, and with a sudden jerk 

 inward the refuse was dropped outside the tube. He also noted that where the tube 

 was broken posteriorly the aperture was closed by a translucent brownish secretion, so 

 that the respiratory and other functions could thus be efficiently carried on. 



Ellis l (1755) gives fairly good figures of the annelid Avith its opercular crown, and 

 observes that the tubes are interesting as showing a series of saucer-shaped enlargements, 

 and this observation is correct, though such has not hitherto been observed in the 

 Scottish specimens — it may be from their incompleteness. Ellis thought the animal made 

 a cover of sand at these enlargements for protection, and when alarmed retired into the 

 narrow part of the tube. Mr. Arnold Watson sent a fine example from the English 

 coast in which these enlargements occurred at the ends of the tubes throughout the 

 entire surface. 



Guettard (1774), after Reaumur and Ellis, gives a description of this and another 

 species under the title Psamatotus, with a brief historical account from Reaumur 

 onward, and shows that Linn gens at first placed Sabellarian tubes amongst the tubiporous 

 corals, and that Baker erroneously located a true polyp in the tube of the annelid. 

 Guettarcl's examples of the annelids were chiefly attached to shells. His figure is 

 quite recognizable. He termed it Penicillits — Pinceau. 



Pennant's figure (1777) sIioavs the tubes in mass, and he terms the species Sabella 

 rudis, correcting in the subsequent edition the name to Sabella alveolata. 



This is the Alveolaria arenosa of Leach in the British Museum, from Sandgate, Kent, 

 and termed by Dr. Johnston Sabellaria crassieornis. 



Donovan (1801), in his ' British Shells,' gives a bold figure of the funnel-shaped 

 ends of the tubes, and specially refers to it. His figure represents even a more expanded 

 condition than that on Plate CXXXIII, fig. 15. 



Montagu (1805) noticed that the aperture of each tube is considerably expanded, 

 and the whole has somewhat the appearance of a honeycomb. The length of some of 

 the tubes Avas nearly 3 inches. 



Cuvier terms it AmpMtrite alveolata, and gives an enlarged coloured draAving of the 

 animal protruding from its tube, and a coloured view of the operculum — more elongated 

 (elliptical) than 8. spimdosa. 



De Blainville, again, figures the tubes with both cylindrical and dilated ends. 



Sabella alveolata Avas included by Milne Echvards in the 1836—49 edition of Cuvier 

 under the Ainphitrites, along Avith Terebellids, Amphictenicls and Chloroemids. 



1 'Nat. Hist, of the Corallines/ Ellis's figure, or one resembling it, lias been copied by 

 various authors, such as Chenu (ll e livr., pi. ii, fig. 7). 



