24 PROCEEDINGS OF THE NATIONAL MUSEUM vol.70 



stated that only the internal division reaches the mandible, the 

 external portion having insertion upon the cartilage adjoining. This 

 muscle is neither figured nor mentioned for GloMoce'phala. 



INTEEEAMAL MDSCULATUEE 



The powerful monogasfricus, or rostral belly of the more usual 

 digastricus, has origin from the lateral 30 mm. of the basihyal, and 

 insertion along practically the entire medial margin of the mandible. 

 Its original end is especially heavy. 



Schulte terms this muscle the hyomandibularis. In Kogia the 

 origin was just twice as long, relatively speaking, for it was from 

 the entire basihyal instead of the terminal half. And in this genus 

 the insertion is much more restricted than in Neomeris. Balaenoptera 

 has a very large muscle associated with the cavum vertrale, which 

 Schulte terms the sternomandibularis. His description of this is so 

 complicated that to a reader it is somewhat ambiguous. He finds 

 that it is imperfectly divisible, and one of the slips he considers 

 to be homologous with the anterior belly of the digastric. An opin- 

 ion of value certainly can not be offered without examination of a 

 specimen, and no further discussion is here attempted. The anterior 

 belly of the digastric of Glohiocefliala is figured as being large, but 

 evidently with a more restricted insertion than that of Neomeris. 



With strong origin from the entire border of the basihyal and 

 from the usual medial raphe, the fibers of the mylohyoideus extend 

 cranio-laterad to an insertion along the medial margin of the man- 

 dible. This type of mylohyoid seems to be rather uniform in the 

 Cetacea. 



MUSCLES OF THE TONGDE 



The slender and rather weak styloglossus has origin from the 

 cranial border of the stylohyal some 20 mm. from its termination. 

 It runs practically parallel with the neighboring portion of the 

 mandible and is inserted into the lateral border of the tongue. This 

 muscle seems to be very similar in Kogia^ Glohiocephala, and Pho- 

 caena, but Schulte failed to find it in Balaenoptera. 



The hyoglossus has origin from the more cranial portion of the 

 stylohyal and the ceratohyal, with a few fibers from the basihyal. 

 The fibers then converge and extend into the medial part of the 

 tongue. 



In Kogia and Phocaena this muscle is very similar to that of 

 Neomeris. In the other two genera considered it seems to be in- 

 separable from the genioglossus. As in Kogia and Phocaena^ this 

 muscle has no attachment to the hyoid. Origin is from the tissue of 

 the ventral surface of the pharynx craniad of the hyoid system, and 

 insertion is into the tongue. In Balaenoptera and Glohiocephala 



