INTERNAL MORPHOLOGY 

 THE CAMAROPHORIUM 



Definition. — For many years prior to 1929 paleontologists had re- 

 ferred to the internal structure on the crest of the median septum of 

 the brachial valve of Stenoscisma as a "cruralium," although many 

 noted its difference from the normal cruralium of the Camarotoechiinae 

 (e.g., Weller, 1914). Kozlowski (1929) demonstrated its difference 

 from that structure, and designated it the camarophorium. The name 

 was derived from the name of the genus Camarophoria King (1850), 

 equivalent of Camerophoria King (1844) and Stenoscisma Conrad 

 (1839). Cooper (1956a), who was familiar with Kozlowski's paper, 

 inadvertently (oral communication, 1960) coined the term "toryni- 

 dium" for the same structure. Because the earlier term was well estab- 

 lished, and unambiguous, it is here retained. Its spelling is based on 

 the correct etymology of Camarophoria. 



Description. — The camarophorium, as defined by Kozlowski ( 1929) , 

 includes both the median septum of the brachial valve and the expan- 

 sion of its crest into an elongate trough (pis. 22-24; fig. 1). It does 

 not include the short plate that unites the posterior part of the midline 

 of the trough with the underside of the hinge plate. That plate, sepa- 

 rate from the camarophorium itself, is called the intercamarophorial 

 plate (Licharev, 1936). 



The septum is a normal septum duplex, as shown by Kozlowski 

 (1929) and by serial sections of specimens of Atribonium (fig. 7c), 

 Coledium (fig. 21), Stenoscisma (fig. 25), Cyrolexis (pi. 6, figs. 4, 

 4a), and Camerisma (fig. lie; pi. 8, fig. 2a). The expansion of 

 the crest of the septum forms a trough that broadens slightly toward 

 the anterior and normally is extended slightly at the anterior midline. 

 The crest of the septum, and consequently the base of the trough, 

 curves gently ventrally forward, giving the trough the shape of a shal- 

 low spoon. The combination of trough and septum constitute the 

 camarophorium. 



The intercamarophorial plate extends from the underside of the 

 hinge plate to intersect the midline of the trough of the camarophorium 

 (Kozlowski, 1929). It is present only in the posterior half to two- 

 thirds of the camarophorium, its anterior extent in some genera is only 

 slightly greater than that of the hinge plate from which it derives. The 

 anterior of the camarophorium is simply spoon-shaped, without a 

 median septum or ridge. 



The septum of the camarophorium is present in the extreme poste- 



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