SCHULTE, SEI WHALE. 415 



tendineus at the apex of the orbit, which on its ental aspect is associated with the fibrous origin 

 of the retractor. The four recti broadening towards their insertion, together with the superior 

 oblique, form a complete muscular cone which is deficient only by a narrow gap between the 

 oblique and the internal rectus. Elsewhere the border of one muscle is in contact with that 

 of its neighbor and the whole is held in place by a thin but firm investment of fascia, through 

 which the obliqui pass to their insertions upon the sclera. Of each of the recti a majority of 

 the fasciculi pass on into the lids and there expanding find an insertion into the fibrous tissue 

 on the deep surface of the orbicularis. These extensions to the eyelids, first found by Hunter, 

 constitute collectively the musculus palpebralis of Weber. 



Weber describes exchange of bundles between the recti which I take him to mean of their 

 palpebral portions, for elsewhere in this foetus the muscles were clearly defined from one another. 

 The superior rectus was partially divided in both eyes by a longitudinal cleft, so that at first 

 it appeared as though a discrete levator were present. This was not the case, for both portions 

 sent bundles to eyelid as well as globe, and the cleft did not extend throughout the length of 

 the muscle. The inferior oblique arises from the maxilla near its articulation with the zygoma. 

 It is directed laterad and caudad to the border of the inferior rectus, where it turns on itself, 

 passing between the deep and superficial fasciculi of the palpebral extension, by which it is main- 

 tained in position. Its belly then expands into a broad insertion upon the sclera, which begins 

 ectal to the mesial half of the inferior rectus and continues obliquely to the level of the ventral 

 border of the external rectus. All of the peculiarities of this muscle have been minutely 

 described by Weber. From the deep surface of its sheath a few fibrous strands could be fol- 

 lowed to the zygoma, which no doubt reinforced the muscular support afforded by the cleft 

 in the palpebralis. The insertion beginning ectal to the inferior rectus occurs in other cetacea 

 but is not confined to this order (Weber). In this foetus it is broad and continuous as in B. 

 Sibbaldii ( = B. musculus) and not divided into two slips as in B. rostrata (= acuto-rostrata). 

 The superior oblique, like the inferior, is fleshy to its insertion. The belly turns through the 

 palpebral extension of the superior rectus and is maintained in position in a manner similar 

 to the inferior. I could not find a fibrous trochlea, though it is present in adults of the genus 

 (Weber). 



The musculus retractor oculi (m. choanoides) arises from the ental contour of the annulus 

 tendineus. Its fibrous tube is deficient on its' nasal aspect to give passage to the optic nerve. 

 From this tube a circular muscle arises, which distad divides into four slips, separated by tri- 

 angular intervals. Throughout its length it is firmly adherent to the supportive tissue of the 

 underlying vascular plexus. It is inserted into the sclera near the equator of the globe. It is 

 innervated by the abducens (Weber). 



Muscles of the tongue. The genioglossus is a broad sheet-like muscle arising from the 

 ental aspect of the ventral margin of the mandible from the symphysis for about one half of 

 its length. Its mesal fasciculi pass sagittally caudad, those of more lateral origin obliquely 

 mesad and caudad. On reaching the mesal margin of the hyoglossus all save the most caudal 

 fasciculi turn dorsad to be inserted into the dorsum of the tongue. Here between the muscles 

 of the two sides is a considerable oval interval filled with fat, to the increased development of 

 which may be due the peculiarly flabby character of the tongue in the adults of this genus. The 

 most caudal fasciculi unite in a raphe which broadens to a tendinous sheet towards the hyoid 

 to which it is but loosely attached, the dorsal turn into the substance of the tongue being pre- 



