BRITISH NEMERTEANS, AND SOME NEW BRITISH ANNELIDS. 383 



teristic, the inner or free surface of the coat being covered with a vast number 

 of these elongated glandular structures. These are the baccillary bodies described 

 by Dr Max. Muller,* but I have never observed in the British species any of the 

 urticating organs mentioned by this author. The minute structure of the wall 

 of the proboscis agrees with that in Borlasia, only the lozenge-shaped portion 

 (g, Plate XII. fig. 1) in some specimens was longer than in B. oliracea, from the 

 more gradual slanting of the fibres to the exterior. 



In Cephalothrix the papillae of the proboscis are acicular, and they are longest 

 towards the anterior part of the organ (Plate XI. fig. 9). In transverse section 

 the walls present a simpler structure than in Borlasia ; and, though in the living 

 animal an external circular and internal longitudinal muscular coat are apparent, 

 the tissues become so confused after mounting, that I have not yet satisfactorily 

 unravelled them. 



Under the action of powerful irritants, such as alcohol, the animal detaches, 

 in its spasms, both the anterior and posterior connections of the proboscis at 

 once, so that the extruded organ remains in its ordinary condition when expelled, 

 and is not turned inside out. In Cephalothrix, again, it sometimes ruptures near 

 the ganglia, and is drawn backwards by the ribbon of attachment and its own 

 elasticity; and the animal seems to be unaffected by the injury, which regeneration 

 soon repairs. I have never seen the worm use the proboscis for any purpose; 

 and though M. Van Beneden has observed it extruded in his Cerebratulus CErstedii 

 (which is only Dal yell's Gordius taenia), and threatening its prey, I fear it could 

 not do much harm. The life-like vermicular motions of this muscular tube, both 

 in situ and when cast off, have misled Mr Beattie| and others, so that they 

 have described the organ as a young animal, and the possessor as viviparous, or 

 else have considered the expelled portion a parasite. This is at once apparent 

 on examining Mr Beattie's specimen of the supposed young animal in the British 

 Museum. £ The proboscis is reproduced in the same manner as in Ommatoplea; 

 and the discarded organ, if not ejected, may be seen floating in the proboscidian 

 cavity amidst much granular debris. Sir J. Dalyell§ states that the usual 

 colour of the proboscis in Linens longissismus is vivid red ; our specimens have 

 generally had white or faintly pinkish organs. 



M. Van Beneden || does not mention the tissues to which the muscular 

 retractor of the proboscis is attached in his Nemertes communis, and speaks of it as 

 suspended freely in the cavity of the body, like the digestive tube of the Bryozoa. 

 A further remark with regard to the organ in Cerebratidus CErstedii (G. taenia. 



* Observat. Anat. de Vermibus quibusdam Maritimis, Berolini, 1852. 



f Ann. Nat. Hist., 1859. 



J Dr Baird, in describing Serpentari/c Berryi, n. sp., also alludes to the very common practice 

 of ejecting the proboscis (not the alimentary canal) after immersion in spirit. It is a habit common 

 to all the Nemerteans. — Proceed. Zool. Soc. Feb. 12, 1866. 



§ Pow. Creat. vol. ii. || Op. clt. p. 10. 



