ON AMPHILINA PARAGONOPORA 63 



the proboscis is also long, and even in the T e t r a r h y n c h u s 

 scolex in which the four retractor muscles of the four pro- 

 boscides reach, as in Amphilina, to the hind end of the 

 ' segment ', each proboscis is at least one-fifth the length of 

 its retractor muscle. 



Wagener (1858) and Lang (1881), on the other hand (neither 

 of whom can be supposed to have recognized the fact that the 

 fibres of the large proboscis ' muscle ' are individually con- 

 nected with the giant cells which Salensky called ' problematic '), 

 adopted the view that the whole of the proboscis ' muscle ' 

 is a bundle of elongated ducts connected with ' Speichel- 

 driisen ' (!) lying in the parenchyma, the ducts being supposed 

 to open on the surface of the proboscis. Needless to say, 

 apart from the superficial resemblance of the anchor-cells to 

 gland-cells (and ganglion-cells !), and the necessity of adopting 

 an alternative to the ' retractor ' theory, there is no justifica- 

 tion whatever for this view, though it has been adopted both 

 by Pintner and Janicki and referred to in such well-known 

 general works as Bronn's ' Thierreich ' and Lankester's 

 ' Treatise on Zoology '. The three obvious facts (evident in 

 any series of well-stained longitudinal sections through the 

 proboscis), viz. (1) that there is no trace of a lumen in the 

 individual fibres, (2) that the fibres are distinctly composed of 

 muscle substance, and (3) that the supposed ducts do not reach 

 the surface of the proboscis,^ are sufficient by themselves to 

 dismiss this gland-complex theory, quite apart from the further 

 facts, already described, of the greater part of the proboscis 

 being covered with serrated cuticle (the terminal cushion 

 provides far too small an area for the openings of such a large 

 number of supposed ducts) and the suggestive twisting of the 

 muscle-fibres anteriorly, and the consideration that it is 

 difficult to conceive the necessity for the existence of such an 

 enormous gland — a gland which, with its ducts, extends 

 throughout nearly three-quarters of the substance of the body. 



The proboscis muscle then, being neither a retractor nor 



^ Janicki, in his fig. 9 of the ' vordere Korpcrspitze', expressly refrains 

 from figuring tlie supposed ducts of his ' Frontaldriisenzelle ' ! 



