DE. J. MITRIE OX THE ORGANIZATION OF THE CAAING WHALE. 277 



spinal column, a single, thick, massive tendon. Besides the foregoing, both longissimus 

 and spinalis possess a deep series of long, nan'ow tendons, one to each vertebra, but 

 mingled or bound together by interstitial fleshy fibres. It results that these dorsal 

 muscles act upon every vertebra independently, whilst at the same time the motor 

 power of the fibro-cartilaginous tail is derived from the lengthened and more powerful 

 cords ; for from these there extends backwards a firm, glistening fascia, spread over and 

 incorporated with the deep tail-substance. The latter, composed of closely packed 

 parallel fasciculi, something of the consistence of the dorsal fin, traverse the thickness 

 of the tail, and here and there have slits for the passage of the nutrient vessels. 



Supracaudal. The single muscle (or compound muscle, if so regarded) to which I 

 give this appellation lies external to the last, along the narrow portion of the caudal 

 vertebrae, and on the upper side of the transverse process. Narrow in front, where 

 fleshy, it widens somewhat and forms a tolerably thick fusiform belly, which again 

 flattens and becomes tendinous. In its course it is attached partly to the vertebral 

 bodies and partly to the transverse processes, sending off a special tendon to each of the 

 latter. Posteriorly the flattened tendon lies against the sides of the bodies of the ter- 

 minal vertebrae, and ultimately is lost in the general expansion of the upper surface of 

 the tail-flukes. For further remarks, see infra. 



Coming under the denomination of multifidus spinfe and rotatores spinte, because of 

 their position, origins, and insertions, are a great number of musculo-tendinous bundles, 

 very apparent and well marked, but difficult individually to separate and define. These 

 are still more numerous and closely packed together in Lagenorhynchus than in Globio- 

 cephaJus, in consequence of the number and approximation of the vertebrae in the 

 former. Stannius recognizes such a deep set of muscles in the Porpoise ; and I can 

 corroborate his observation in that genus. Their general arrangement is by tendons 

 from the dorsal metapophyses, and trending forwards and inwards are attached muscu- 

 larly to the sides of the roots of the spinous process in advance of their origin. The 

 most anterior one is fixed to the atlas. 



But there are besides a deeper layer of fascicles springing tendinously from the spines 

 and dorsal arches, and these becoming fleshy are inserted into the transverse processes 

 of the same vertebrae — doubtless semispinales, as Stannius' names them in Phoccpiia. 

 He alludes, moreover, to another set of fasciculi, close to the last, and connected with 

 the vertebral processes, but he has not named them. 



In the four-limbed mammals generally there are three, or at most four, muscles 

 described as occupying the iliac region, viz. the psoas major, psoas minor, iliacus, and 

 quadra tus lumborum. But in Cetaceans, as most writers state, there is only one enor- 

 mously large inferior lumbo-caudal muscle, which, at first sight, might be supposed 

 either to represent the psoas magnus alone, or the psoas minor, iliacus, and quadratus 

 lumborum incorporated along with it. Whatever relation exists, division at least is 

 ' " Muskeln des Tummlers," MUU. Archiv, 1849, p. 30. 



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