ON THE GENERAL MORPHOLOGY OF THE MYXINOID FISHES. 697 



The two heads pass into a common and very short but powerful tendon which 

 arises from the ventral surface of the opposed heads, but chiefly from the external 

 ventral surface, and which in one dissection was inserted into the pad of soft pseudo- 

 cartilage at the anterior extremity of the external bar of the anterior segment of the 

 basal plate, dorsal and external to the lateral labial cartilage as it was winding over 

 the pad to fuse with the external bar. There was no union of the two heads before 

 passing into the tendon, such as described by P. Furbringer. In another specimen, 

 however, it was inserted largely into the dorso-posterior surface of the lateral labial 

 itself as it was passing over the pad. In Bdellostoma, according to Allis, the insertion 

 is into " the lateral labial cartilage, or in the tissues near that cartilage." P. Fur- 

 bringer states that the tendon is inserted into the lateral labial only, which, however, 

 he did not recognise to be cartilaginous at this region. J. Muller also gives this 

 insertion in Bdellostoma. In my sections I find that the tendon is large, diffuse (not 

 easily defined), and attached to the surrounding fascia. It passed at once on to the 

 dorsal surface of the pad of pseudo-cartilage, dorsal and largely posterior to the lateral 

 labial (cp. fig. 1 of my first Part), which it certainly did not reach. Further, the two 

 heads fused before reaching the tendon (as described by P. Furbringer), and otherwise 

 the separation of the two heads was very difficult, although their origins were perfectly 

 distinct. The indefiniteness of the tendon and its connection with the surrounding 

 fascia would seem to explain the discrepancies in the statements above. 



The palato-coronarius draws the anterior extremity of the basal plate, and hence 

 the ventral margin of the mouth upwards and backwards. 



12. M. copulo-tentaculo-coronarius. (Figs. 3, 9, 10, 11, cp. t. c, cp. t. c'., cp. t. c" .) 



J. Muller, Zweikopfiye Herabzieher des Mundes (p. 259). 



P. Furbringer, Copulo-tentaculo-coronarius + Tentacularis anterior (pp. 12 and 17). 



A curious and complex muscle, the anterior division of which is regarded by P. 

 Furbringer as a separate muscle, having an independent origin from the base of the 

 fourth tentacular cartilage, and called by him the tentacularis anterior. I have, 

 however, invariably found, both in dissections and sections, that the latter is, with the 

 exception of a few fibres, simply the forward continuation of the first head of the 

 copulo-tentaculo-coronarius, and hence cannot be separated from it. 



The copulo-tentaculo-coronarius arises as a first or principal head (cp. t. c.) from the 

 median border of the external bar of the anterior segment of the basal plate at about 

 the middle of its length, and some fibres also from the tough fibrous tissue connecting 

 the external and internal bars (fig. 11). P. Furbringer states that some fibres arise 

 from the outer margin of the internal bar. In the sections this head is reinforced by 

 a small second head from the ventro-external fascia of the origin of the external head 

 of the copulo-ethmoidalis, and which passes forwards external to the dorsal portion of 



