THE SKELETON OF THE BLACK BASS. 



317 



In the latter, in Micropterus, we bave a posttemporal {Pst. T.), a posterotemporal 

 {Psto. T.), a teleotemporal (T.), a lower teleotemporal (T'.), a hypocoracoid {Hyo. c), a 

 hypercoracoid (Hyp. c), and a proscapula (P. 8c.). Now the Mteral or the pectoral 

 fins in this bass are connected with the shoulder girdle through the intervention of 

 four little bones, called actinosts (flg. 7, Ast.); they are very small, graded in size, and 

 are formed somewhat like little hour-glasses or dice-boxes, being enlarged at their 

 articular ends and constricted at the middle. Anteriorly these actinosts articulate 

 with the posterior border of the conjoined hyper- and hypo-cor:icoids, while poste- 

 riorly they aflbrd support and attachment for the bony rays of the pectoral fin (P/.). 

 In the several specimens of black bass 1 have dissected and others I have examined. 



Fig. 6. — Inner aspect of opercular bones, hyoid. syraplectic, and other elements of M. salmoides. 

 Left side, natural size, by the author, from his own dissections. Op-, operculum; S. Op., sub- 

 opercnlum; JPr. Op., preoperculura ; I. Op., interoperculum ; M. J/., liyomandibular; M. PL, 

 metapterygoid ; <Si/ih.., symplectic; lA., interhyal; ^k., quadrate; S. Aj/., epibyal ; (7. Ay.,cerato- 

 hyal; H. Ay., hypohyal. These represent the actual arrangement and relations of these bones 

 in teleostean fishes generally. 



in regard to this point, never any more or less actinosts have been found than four. 

 Therefore it may be just as well not to slight such characters as these in our accounts 

 of the osteology of Pisces, nor depict them in any other way than with extreme accu- 

 racy In figures illustrating the skeleton of any species we may be describing. 



In fishes the pelvic bones vary very widely, both in form and position, but are never 

 attached to the vertebral column as we find them in other and higher vertebrates. 

 As I have elsewhere pointed out, in Micropterus salmoides they are represented by 

 two separate and symmetrical bones that articulate with each other mesially by their 

 inner edges. When thus united they form an elongated isosceles triangle, with its 

 apex held by a ligament in the entering angle behind the proseapuhe. The outer 



