ON AMPHILINA TAKAGONOPORA 61 



able giant cells which B a 1 e n s k y labelled 'pro- 

 blematic'. The 'problematic cells' of Salensky are then 

 simply the attachment or ' anchor '-cells of the large axial 

 muscle. The mere distribution (as seen under a low-power 

 objective) of these anchor- cells, as I shall call them, is evidence 

 that they have something to do with the fibres of the muscle, 

 since in the anterior fifth of the body in which the muscle-fibres 

 are most numerous, the anchor-cells are most plentiful and 

 extend laterally to the region of the testes (PI. 4, fig. 21) ; 

 whereas, more posteriorly, where the muscle-fibres are much 

 fewer in number, the number of anchor-cells is also much smaller 

 and is obviously roughly proportional to the number of fibres 

 in any given zone (PL 4, fig. 21). The continuity of the giant 

 anchor-cells (each as big as the egg-filled uterus in transverse 

 section) with the fibres of the muscle can be easily seen both in 

 longitudinal and transverse serial sections, whereas in whole 

 preparations it is not easy to see the connexion, and this accounts 

 for the erroneous supposition of Salensky that the processes 

 from these ' problematic ' cells become sooner or later attenuated 

 and indistinguishable from the ordinary parenchyma with 

 which they are connected, since he doubtless did not trace 

 these processes through serial sections. All these anchor-cells 

 are elongated and their long axes in all cases lie in a plane at 

 right angles to the long axis of the body (PI. 3, figs. 4, 5) — 

 a significant fact. These long axes are, in the case of cells 

 occupying the axial region of the body, disposed vertically 

 (the muscle processes arising from either their dorsal or ventral 

 ends — PI. 3, fig. 4), but anteriorly, in those cells which are 

 situated nearer the sides of the body, the long axes are often 

 obliquely inclined towards the median axis (PI. 3, fig. 5). 

 Cytologically the anchor-cells are, as Salensky remarked, not 

 unlike nerve-cells, and, indeed, they may be neuro-muscular 

 in function, though they apparently have no connexion what- 

 ever Avitli the main nervous system of the worm. Each cell 

 (PI. 4, figs. 22, 28) contains a nuckais (with a conspicuous 

 nucleolus) which lies in a small island of chromatophil cyto- 

 plasm (very evident in indigo-picro-carmine preparations, in 



