602 RECORD OF SCIENCE FOR 1886. 



of a cretaceous species, Ryhodus duhrisiensis, have beea studied by Mr. 

 A. Smith Woodward, of the British Museum, with reference to this 

 question. Without going into details, it may be observed that Mr. 

 Woodward thinks that "on the whole, the form of hyoid arch" devel- 

 oped in this type bore " a greater resemblance to that of the Notidan- 

 idse than to that of any other living family; it agrees in the fact that 

 the hyomandibular and ceratohyal are most contracted at their i)oint 

 of union, but the elements are somewhat stouter than those both of 

 Eeptanchus and HexancliusP He concludes that "it must suffice at 

 present to add that, though there are well preserved pterygo-quadrates" 

 from both the different geological horizons in which remains of the 

 skeleton have been found, " there appears to be none but the most un- 

 certain evidence of an articular facette on the otic process in any; and 

 if this observation can be confirmed it will become of considerable in- 

 terest when taken in connection with the fact pointed out by Professor 

 Huxley, that the postorbital articulation in the living Heptanchus is 

 only acquired comparatively late in the development of the foetus. It 

 is also interesting to note that one of the Liassic specimens exhibits 

 traces of a persistent notochord, with the arches alone calcified, whereas 

 in the cretaceous form," as has been shown by Mr. Woodward, "there 

 are well differentiated centra." The differences between the anterior and 

 posterior teeth are likewise more marked in Hybodus dubrisiensis than 

 in any of the earlier species of which satisfactory remains are known. 

 '•It would appear indeed that there is distinct evidence of specializa- 

 tion, as the Hybodonts are traced through the Mesozoic period, and it is 

 almost certain that future research in regard to structures other than 

 teeth will lead to the subdivision of the multitudinous forms hitherto 

 groui^ed under one generic name." (Proc. Zool. Soc. London, 1886, pp. 

 218-224, pi. 20.) 



The question still remains an open one as to the degree of relation- 

 ship of the Ilybodonts to the Heterodontids, for it is scarcely probable 

 that there is any close relationship between the former and the Notid- 

 anids. 



Fishes ])roper, or Teleostomes. 



Fishes with males larger than females. — It has been believed by some 

 ichthyologists, and especially affirmed by Dr. Glinther, that " with re- 

 gard to size, it appears that in all teleosteous fishes the female is larger 

 than the male." This statement is altogether too general, and various 

 exceptions are knowm. It is indeed possible that in a large proportion 

 of those fishes whose males are distinguished by brilliancy of coloration 

 or other striking secondary sexual characters, while the females are 

 comparatively plain, the males are larger than the females. Such is 

 the case at least with certain species of the family of Gobiesocids. These 

 fishes are common in certain waters, although rather local and rare 

 along the coasts of eastern America. Several species are however 



