THE SKELETON OF THE BLACK BASS. 



By Dr. R. W. SHUFELDT. 



Upward of twenty years ago a special interest was taken by me in the osteology 

 of the large-mouth black bass {Micropterus salmoides) from having discovered in the 

 skeletons of one or two specimens of that species a pair of free ribs articulating with 

 the base of the skull or occiput. As this peculiar anatomical character had never 

 been noted by me before in any of the true bony fishes (Teleostei), it was at the time 

 deemed worthy of scientific record, and so, under the title of "Osteology of the large- 

 mouthed black bass (Micropterus salmoides),^' there was printed in Science, of Cam- 

 bridge, Mass., May 2, 1884, a brief account of this interesting point in the skeleton 

 of Micropterus. 



It was there stated that this peculiarity "consists in a pair of freely articulated 

 ribs at the base of the occiput. Their heads are received in a shallow facet on either 

 side situated just above and rather internal to the foramen for the vagus nerve. 

 Immediately below each rib occurs the projection of bone that bears upon its entire 

 posterior aspect one of the pair of articular condyles for the first free vertebra of the 

 spinal column. Still beneath these condyles is seen the conically concave facet for 

 articulation, with a similarly formed surface occurring on the centrum of the vertebra 

 just mentioned, and the one which I believe would be described as the atlas." This 

 pair of ribs is directly in sequence with the abdominal ribs on either side. Their 

 occurrence in this situation might be accounted for by saying that several of the 

 anterior vertebrae of the column had been absorbed by the occipital elements. Mr. 

 Bridge found such a condition in Amia, though no free ribs were present [Journ. Anat. 

 and Phys., xi, 611, London, 1877). In further commenting upon this it was added 

 that "in the cranium of Micropterus, however, I should think that this would be highly 

 improbable. Both the first and second vertebra of the spinal column of this bass 

 support each a pair of free ribs, and a mid-series of the other abdominal ribs bears 

 epipleural appendages. Dr. Gunther states, in his account of the osteology of the 

 Teleostei, in the article ' Ichthyology' of the Encyclopaedia Britannica (vol. xn,9thed.), 

 that 'the centrum of the first vertebra or atlas isvery short, with the apophyses scarcely 

 indicated. Neither the first nor the second vertebra has ribs.' I have a yellow perch 

 [Perca flavescens) in my possession where both of these vertebrae support a pair of free 

 ribs." In conclusion, I added that " should an examination of the young of the black 

 bass show that none of the anterior vertebrae of the column were included with the 

 occipital segments, but that these ribs are truly occipital ribs, then they become of 

 interest from several points of view." 



This discovery was made in March, 1884, and, as has been noted above, was 

 published the following May, and attracted the attention of no less a distinguished 



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