66 DR. H. GADOW ON THE SUCTORIAL [Feb. 20, 



In the next stage E, the right and left halves separate into secondary 

 tubes through the fissures at g and h becoming completed. The 

 curling inwards of the free edges leads to the formation of four more 

 or less complete secondary tubes, two external and two median. 

 Each of these four tubes divides again on its median line ; and thus 

 are formed eight tertiary, or perhaps rather four double tubes. 

 These latter tubes break up again and again, but without forming 

 new tubes, forming only the so-called brush of the tongue. This 

 consists of about 80 or more horny bristles in Prosthemadera. 



A similar arrangement is met with in the few other MeliphagincB 

 which I have been enabled to examine, viz. Mohoa, Anthornis, and 

 Meliphaga. 



The most important differences between the Nectariniince and 

 MeliphayincB in regard to the horny part of the tongue are therefore, 

 first, that the tongue in the former does not form more than two 

 tubes, whilst in the latter it is broken up dichotomously into 2, 4, 

 8, etc. ; secondly, that in the MeliphagincB it is always the external 

 border of every tube that becomes laciniated, but in the Nectariniince 

 it is the inner or median border, whilst the external margin remains 

 entire. 



In the Trochilidce we meet with a third sort of tubular tongue. 



The tongue of these birds is double right down to the unpaired 

 part of the us entoglossum, whilst each of the two distal prolonga- 

 tions of the entoglossal bone or cartilage is surrounded by a horny 

 sheath, which is curled upwards and inwards, in a similar fashion to 

 what we have seen in the Nectariniince. In many species the outer 

 and inner edges of these tubes, however, are entire, and not laciniated. 

 Thus the Trochilidse have developed the highest form of tubular 

 tongue. 



The Muscles of the Tongue. 

 Nectarinia splendida. 



M. mylo-hyoideus. This muscle fills the distal two thirds of the 

 mandibular space ; it arises from the inner aspect of the mandibles, 

 and throughout its length fuses with its fellow of the other side. 

 Its fibres run in a transverse direction. Near the anterior margin 

 of the serpi-hyoid muscles, the mylo-hyoid is doubled up and is 

 inserted into the soft and transversely wrinkled outer sheath of the 

 basal part of the tongue proper (Plate XVI. fig. 1). 



M. serpi-hyoideus is the most superficial of the muscles of the 

 hyoid apparatus. It occupies the basal or proximal half of the space 

 between the mandibles ; it arises as a narrow semitendinous slip 

 from the posterior and upper angle of the processus serpiformis 

 mandibulse immediately behind the masseter nmscles. Its fibres are 

 directed obliquely forwards and downwards, fusing with those from 

 the other side in the middle line, without, however, forming a di- 

 stinct linea teudiuea. The anterior most distal part of this muscle 

 is partly attached to the basihyal bone and to the sides of the stylo- 

 hyoid muscle near its insertion. Whether these little lateral slips of 



