ANATOMY OF BALDEN OPTBEA BOSTRATA. 
235 
median line, the latter lying on a plane superior was inserted into a line leading from 
the centre of the margin for about 1 inch in extent. 
The cornua or ossa styloidea were distinct, curved, cylindrical bones, and were arti- 
culated internally by short and firm fibrous and fibrocartilaginous bands to the sides of 
the anterior portion of the body, as before described. In Globiocephalus Svineval the 
union is accomplished by a prolonged fibrous rounded band. Eschricht and Keinhardt 
picture a similar elongated intervening ligament in the Mysticete. 
At their external extremities these bones were somewhat club-shaped, and were closely 
united to the base of the skull by the interposition of a strong fibrocartilage ; from their 
anterior or concave edge they gave attachment to the muscles of the tongue, viz. the 
hyoglossus and genioglossus ; posteriorly three muscles arose from each of them ; first, 
the superficial hyokeratic, which occupied the inner third ; second, the deep hyokeratic, 
which had its origin from the middle and part of the inner third of the bone ; this 
muscle was prolonged posteriorly and superiorly to the last described; and third, the 
keratopharyngeus, which took its origin from the remaining outer third of the cornu. 
No muscles covered their fibrocartilaginous cranial articulation; but in Globiocephalus 
Svineval the craniostyloid articulation was covered by a short flat muscle, the squamo- 
styloid, which, arising from the squamous bone above the articulation, and crossing over 
the fibrocartilage, went to be inserted into the styloid bone at its cranial third. 
Another muscle in this animal, the stylohyoid, of a pyriform shape, arose from the 
squamous bone behind the styloid articulation, and was inserted into the extremity of 
the posterior cornua or lateral angle of the body of the hyoid bone, in its course crossing 
the external carotid artery and the lingual nerves. 
Larynx. 
The framework of the larynx was composed of four true cartilages, viz. thyroid, 
cricoid, and two arytenoid. 
The thyroid formed the lateral and inferior boundary of the laryngeal cavity, and was 
composed of two symmetrical halves or alee united by a central isthmus ; each ala exhi- 
bited four edges bounding two surfaces. The anterior edge was concave forwards and 
smooth, it measured 4 inches in length ; the posterior edge was 84 inches in length, and 
was deeply excavated ; it terminated internally in a triangular prolongation 2 inches in 
length, with its apex directed backwards. 
The external or lateral border was convex and slightly prolonged forwards to form 
the anterior cornu, from whence the thyrohyoid muscle had its origin ; posteriorly this 
border was prolonged into a round digital process which formed the posterior cornu, 
whose extremity was connected by fibrous tissue to a well-marked tubercle situated on 
the posterior and lateral aspect of the cricoid cartilage. The entire extent of this 
external margin, measured from its anterior to its posterior cornu, was 7 inches, and to 
it the inferior constrictor of the pharynx was attached. The inner border was formed 
of two distinct parts, an anterior and posterior ; the former, about an inch in extent, was 
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