RELATIONS OF ANTERIOR VISCERAL ARCHES. 65 



articulate with the skull in many hyostylic types, and on the 

 other hand in the amphistylic Notidanns both arches do not articu- 

 late with the skull since the hyomandibular is connected with it 

 only through ligaments (Gadow, '88, PL 71, Fig. I, A). 



Gadow (1888). 



Gadow apparently uses the terms in their etymological signifi- 

 cance, rather than with the limitations imposed by established 

 usage. Thus he speaks (p. 455) of the " autostylic condition 

 of the Notidanidce " (the " amphistylic " of authors) and applies 

 the same term to the Amphibia (p. 481) and the Dipnoi (p. 459), 

 evidently having in mind the self-sufficiency in all these cases of 

 the first arch as its own suspensorium ; so too, " simple autosty- 

 lic " (p. 459) apparently refers to the ancient and generalized 

 condition from which the modern modes have been derived 

 (cf. " palaeostylic," proposed above) and in which the oral arch had 

 not yet begun to borrow support from the hyoidean arch. Again 

 Gadow applies " holostylic " (p. 458) to Chimcera, Ceratodus and 

 Cestracion evidently with reference to the functional ligamentous 

 union of the upper jaw with the cranium in Cestracion and to its 

 fusion therewith in Chimcsra and Ceratodus. " Amphistylic " 

 in its etymological sense serves to describe the conditions in 

 "most selachians " (p. 481), in which both oral and hyoidean 

 arches are suspensorial, while etymologically the rays are pre- 

 eminently "hyostylic" (p. 481) since the dorsal element of the 

 hyoidean arch, the hyomandibular, is the sole suspensorium (cf. 

 our " euhyostylic," p. 56, supra], 



But while this bold and highly suggestive use of terms has 

 finally bred in me several clarifying ideas I cannot deny that 

 formerly, wishing to refer to isolated passages of Gadow's work, 

 I experienced a most baffling uncertainty as to his meaning. 



Smith Woodward (1897). 



" Among the fishes existing at the present day there may be observed 

 two distinct plans of cranial structure, between which no definitely inter- 

 mediate conditions can be recognized. In Chimcera, Protopterus, Cerato- 

 dus and their allies, the upper segment of the mandibular arch is directly 

 fused with the chondrocranium, while the corresponding segment of the 

 hyoid arch is atrophied or absent ; in the Elasmobranchs and the so-called 

 " Ganoidei " and " Teleostei " the same elements are loosely articulated 

 with the chondrocranium, the upper segment of the hyoid arch forming a 



