BIBLIOGRAPHY. 259 



history of Fishes. In the Rays and Sharks the large vitelline 

 spheres are frequently included in horny capsules, called " sea- 

 purses," which project into cornua or cylindrical threads. 



Certain Sharks (c. g., Mustelus, Carcharias) attach themselves, 

 after the manner of the Mammalia, by an umbilical chord to a pla- 

 centa placed in the interior of the female genital organs, and thus 

 constitute a very remarkable exception among the class of Fishes. 

 In other Fishes, as in Syngnathus and allied genera, the young are 

 developed in a peculiar cavity, or incubating organ, opening by a slit, 

 and placed posterior to the anus beneath the tail. It is remarkable 

 that these pouches are found only in the male Syngnathi, while in 

 Scyphius it is the females who carry their eggs free in a mass 

 adherent to the belly. 



REFERENCES 



TO THE PRINCIPAL WORKS UPON THE ANATOMY OF FISHES. 



FOR List of General Works upon Comparative Anatomy, see page 61. 

 Tegumentary System. 



Kuntzmann, in Verhandlungen der Gesellschaft naturforschender 

 Freunde in Berlin, Band 1, 1824, describes and partly figures scales of 400 

 species of fish. 



Agassiz, poissons Fossiles, torn. 1, and in Annales des Sciences Nat. 

 torn. 14 ; in torn. 11 of latter work, consult Mandl, and also his Anat. Mi- 

 croscopique, 2d part. 



Monro, upon Structure of Fishes as compared with that of Man, &c. 

 Edinb. 1785. 



Miiller, Beitragen zur Kenntniss der naturlichen Familien der Fische in 

 Wiegmann's Archiv f. 1843. 



Osseous System. 



Rosenthal, Ichthyotomischen Tafeln. Berlin, 1839. 



Agassiz, op. supra cit., and Cuvier in Hist. Nat. des poissons, upon the 

 Common Perch. 



Bakker, Osteographia Piscium. Greening, 1822. 



Wellenbergh, de Orthagorisco Mola. Lugdun. Batav. 1840. 



Miiller, Vergleichender Anat. der Myxinoiden, Erster Theil. Berlin, 

 1835. 



Bojanus, Parergon ad Anatomen Testudinis. Vilnae, 1821 : good figures 

 of skull of Cyprinus brama. 



Arendt Diss. de capitisossei Esocis structure. Regiom. 1824. 



