DE. J. MUEIE ON THE ORGANIZATION OF THE CAAING WHALE. 279 



noticed a trachelo-mastoid, a longissimus dorsi, a sacro-lumbalis, with a slip supposed 

 to be the homologue of splenius capitis, a levator caudae, a depressor caudse major, and 

 depressor caudse minor. 



Notwithstanding amplitude of nomenclature, and recognition of two or more en masse 

 or separate, the anterior divisions of the various observers present a certain harmony ; 

 but there is less concord of opinion regarding the posterior tendinous parts and infero- 

 lumbar region. Eapp and Stannius differentiate as transversarius superior the com- 

 pound tendinous enwrapping sheath of the longissimus and spmalis as described by me. 

 But the latter, moreover, unites it with the anterior fleshy belly of my supracaudal, 

 and Iraces it forwards to the ribs, thorax, and neck, i. e. includes part of what more 

 strictly is sacro-lumbalis and cervicalis ascendens. Carte and Macalister's levator caudse 

 agrees partially with Eapp's transversarius, and partially with Stannius's caudalis 

 superior. The latter muscle, again, is equivalent to Meckel's flexor caudse lateralis and 

 F. Cuvier's levator caudse, one and the same with my supracaudal. None suggest the 

 superior superficial terminal tendons, or aggregate fibrous investing-sheaths of the 

 longissimus and spinalis dorsi, as the homologues of the levatores caudse externus and 

 internus of other mammals. Yet in every sense they are undoubtedly such, continuity 

 with the dorsal fleshy masses bemg the only special deviation from their usual con- 

 dition. The Cetacean supracaudal, again, offers homology in its posterior short slips 

 with the intertransversarii caudse of quadrupeds, its longer-bellied and more fleshy 

 anterior moiety being occasionally in mammals almost separate from the intertrans- 

 versarii caudse, though not specially recognized as a distinct muscle. In Manatus, 

 however, it is uncommonly well developed, and has been named by me lumbo-caudalis. 

 The inferior depressor caudse of Meckel, depressor caudae minor of Carte and Macalister, 

 caudalis inferior of Stannius, and his unnamed musculo-tendinous caudal bundles, cor- 

 respond with the present infracaudal. 



As regards the depressor caudse of Cuvier and Meckel, the depressor caudse major of 

 Carte and Macalister, this undoubtedly is Rapp's psoas major &c. Stannius viewed it 

 as composed of three divisions, equivalent to the dorsal muscles, and named by him 

 respectively longissimus inferior, sacro-lumbalis inferior, and transversarius inferior. 

 So far I agree with the latter, and therefore differ from Eapp, that the great sublumbo- 

 caudal Cetacean muscle is not purely an ilio-psoas. This latter, I believe, as in 

 Manatus, is all but aborted, certainly not recognizable. The homologue of the 

 Cetacean sublumbar muscle, then, with its tendons and investing sheath, seems to me 

 to be the sacro-coccygeus, whatever its significance as to the dorsal series. My infra- 

 caudal may represent partly inferior intertransversarii caudse or perhaps include infra- 

 coccygeus. 



In default of being unable to determine with accuracy spinal insertions in Glohiceps, 

 I was more fortunate in Laijenorhynchus. In this genus the rectus abdominis tapers to 

 a point at the fortieth vertebra, behind this intermingling with the caudal fascia. The 



