696 MR FRANK J. COLE 



with the cornual cartilage. In the sections it was inserted into the palatine bar just 

 behind the palatine commissure. Shortly behind its insertion the tendon, in the 

 sections, gave off from its external margin a small slip which passed internally under 

 the parent tendon to some loose tissue connected with the roof of the mouth not far 

 from the median line. 



The function of this muscle will be to bend the palatine bar downwards. In 

 Bdellostoma J. Muller curiously describes the insertion of the muscle as the origins 

 and states that it draws the pharyngeal basket forwards. In Myocine he ascribes to it 

 the opposite (and surely the correct) function. 



11. M. palato-coronarius. (Fig. 11, pi. c.) 



J. Muller, Zuriickzicher des Mundrandes oder der Mundknorpel (p. 258). Zuriickzieher des 

 Mundes (p. 330). 



A fairly strong muscle, covered externally by the copulo-quadratus profundus, and 

 having two heads — a large external (pi. c.) and a smaller internal. Between the two 

 heads courses the R. externus of the maxillaris of P. Furbringer. According to 

 J. Muller there is only one head in Bdellostoma. 



External Head. — Commences at the posterior portion of the zone of soft cartilage 

 between the palatine bar and the anterior process of the pterygo-quadrate by some 

 fibres from the external rim of this region, and from thence the origin passes obliquely 

 forwards and inwards on to the ventral surface — first of the zone of soft cartilage above, 

 and then on to the same surface of the palatine bar to meet the internal head, which 

 it does near the internal rim of the cartilage. The two heads are now spread over 

 the entire outer and ventral surfaces of the palatine bar at this region. A short 

 distance in front of the zone of soft cartilage the muscle begins to be detached from 

 the palatine bar, the separation commencing externally, and extending inwards and 

 forwards until completed. The fibres of the external head pass downwards and 

 forwards towards the pad of soft pseudo-cartilage at the anterior end of the basal 

 plate, the fibres somewhat converging as they go. 



Interned Head. — Arises at the above-mentioned region of the zone of soft cartilage, 

 but below, internal and quite distinct from it, mostly from the ligamentous sheet 

 connecting the palatine region with the hypophysial plate about half way between 

 these two cartilages. The head then passes forwards, outwards, and upwards to meet 

 the external head, and where the junction is effected a few or more fibres are con- 

 tributed to this head from the inner ventral surface of the palatine bar immediately in 

 front of the zone of soft cartilage. It is difficult to ascertain how much is contributed 

 by the palatine bar, as the two heads here are by no means easily distinguishable either 

 in dissections or in the sections. The fibres follow the same course as in the external 

 head, but are completely covered by the latter in a lateral view. 



