42 4 HTALINCECIA TUBICOLA. 



He mentions the ovaries in their correct position, and gives an account of other structural 

 features. 



Peach (< Rep. Zool./ Ray Soc, 1847) thinks he had observed this form swimming on 

 the surface of the sea, but Edward Forbes was of opinion that this was merely accidental. 

 A dried form in a tube, or a tube with air in it, might float, but though active on the 

 bottom there is no proof up to date that it is pelagic. 



Dr. Johnston (1865), founding on the absence of pectinate branchise, placed this form 

 under his genus Nothria, He made what he calls a vain attempt to form the tube into 

 a pen. 



Ehlers (1868) included the Onuphis sicula of De Quatrefages under this species, a 

 view not held in the present work. Tauber followed him. 



Schmiedeberg (1882), as indicated, made a chemical examination of the tube and 

 found it analogous to chitin. It would be interesting to compare his results especially 

 with regard to "onuphin'' with those recently obtained by Prof. Irvine 1 at St. Andrews 

 on a polarimetric method of identifying chitin in similar secretions in Crustacea, Mollusca, 

 and Fishes. It may be that onuphin has some relation to mucin. 



Pruvot 2 gave an account of the nervous system of this species in which the cerebral 

 mass is large and pierced by the bases of the posterior lateral tentacles. The anterior 

 lobes give origin to the stomato-gastric system of nerves, and not the oesophageal con- 

 nectives. He shows a single central neural canal in the ventral cord. In the British 

 examples the neural canal is nearer the ventral than the dorsal border. He could not find 

 the ciliated pockets of Semper at the posterior part of the head. He found in the foot 

 two ductless glands connected with the bases of the dorsal and ventral cirri, and a smaller 

 third gland having a similar relation to the cirrus (or papilla) near the exit of the bristles 

 at the tip. 



Arnold Watson 3 carefully describes the valves formed in the tube of this species, the 

 anterior being V-shaped, and the posterior zig-zag. The inrush of sea- water automati- 

 cally closes the valves. The worm carries about its tube in its movements on the surface 

 of the muddy ground it inhabits. From his experiments this observer found that the 

 annelids could renew the valves when cut off and also of course add to their tubes. 



Eisig 4 gives a detailed account of the movements of this species in its tube and when 

 free. In its tube its motion is what he calls geometroid, and when swimming in the free 

 condition he terms its action mastigo-helicoidal. It can secrete a new tube in a day. 



1 'Trans. Chem. Soc./ 1909, vol. xcv, p. 565. 



2 ' Arch. Zool. exper./ 2 e ser., iii, p. 256, 1885. 



3 ' Trans. Liverp. Biol. Soc./ vol. xvii, p. 306, etc., figs. 1 — 4, 1903 ; and i Rep. Brit. Assoc./ Belfast, 

 1902, p. 652. 



4 ' Fauna n. Fl. Neap./ xxviii, p. 263, 1906. 



