404 SCHULTE, SEI WHALE. 



Panniculus carnosus The cutaneous musculature is highly developed, forming an unin- 

 terrupted layer upon the sides and venter of the trunk from the occiput to the beginning of 

 the pedicle and being continued beyond this point by a firm aponeurosis which completely invests 

 the tail. It adheres firmly to the derma, beneath which little or no fat has as yet formed, but 

 is in general separated from underlying structures by a moderate quantity of loose areolar tissue. 

 In the region of the ventral pouch however, it is intimately conjoined with the deeper layers 

 by firm connective tissue, and the whole complex is separated from underlying structures by a 

 great area of very loose tissue, the cavum ventrale. 



As a whole the panniculus falls into two divisions, one dorsal and the other ventral, the 

 two united by a lateral raphe as far cephalad as the flipper, in front of which they overlap, the 

 fasciculi of the dorsal division passing superficially to those of the ventral. This raphe extends 

 from the axilla to beyond the vent, inclining toward the mid ventral line as it passes caudad. 

 Its axillary extremity is attached to the humerus in union with the insertions of the latissimus 

 dorsi and pectoralis muscles, which insert also into the proximal portion of the raphe. At its 

 beginning linear and permitting a slight degree of interdigitation on the part of the inserting 

 fasciculi, it gradually widens into a broad band which merges behind the vent into the apo- 

 neurosis of the pedicle. 



The dorsal division arises from a broad aponeurosis which covers the dorsal muscles and 

 in the midline is connected to the spines of the vertebrae by a vertical lamella which intervenes 

 between the muscle masses of the two sides. Its fasciculi are directed ventrad and cephalad, 

 inserting into the lateral raphe, the dorsal aspect of the aponeurosis of the flipper, and in 

 front of this passing as a thin sheet of scattered fasciculi ventrad across the side of the neck to 

 the intermandibular region, where they sweep rostrad almost to the symphysis. Some of them 

 reach the midline and there interdigitate with the bundles of their antimere; the majority do 

 not extend so far but find scattered insertions into the derma along the side of the ventral pouch: 

 The dorsal division extends sagittally from the occiput to near the middle of the pedicle; here 

 it rapidly narrows, the bundles arising at an increasing distance from the dorsal midline but 

 maintaining their regular arrangement and constituting a continuous sheet throughout. 



The ventral division arises from the ventral midline, its fasciculi showing a tendency to 

 interdigitate with those of the opposite side. To some extent they are separated by a line of 

 fibrous tissue which blends with their deep epimysium but is not firmly connected with the 

 linea alba. At the umbilicus the muscles of the two sides separate to give passage to the cord. 

 Here there is a considerable increase in the quantity of connective tissue, both of the pannicular 

 layer and more especially in the linea alba. The panniculus has a well defined edge and none of 

 its fasciculi are prolonged upon the cord. Sagittally the ventral division extends from the sym- 

 physis mandibularum a short distance beyond the vent. Its fasciculi have a rostro-lateral or 

 dorsal direction and form a continuous sheet. This is very thin in the intermandibular region 

 and very firmly united with the overlying scattered fasciculi of the dorsal division and on its 

 deep surface with the mylohyoid, from both of which it is distinguished by the direction of its 

 bundles. These laj r ers together with a deeper stratum of longitudinal direction constitute 

 the muscular wall of the ventral pouch and form a well defined complex, which is only with great 

 difficulty resolved by dissection into its component elements. The fasciculi of the ventral 

 panniculus can be followed in part to the lips and some of them reach the mandible in front 

 of the insertion of the masseter, but many of them terminate within the intermandibular region 



