ZOOLOGY. C25 



while engaged ^'on work on the palseoiitology of Pennsylvania." First, 

 be louud in wliat he calls tlie "Bloonifield sandstone," which "lies at 

 the top of the variegated shale or marl, the middle portion of the great 

 mass of the Onondaga," certain remains analogous to those occurring 

 in the Ludlow beds. The Ludlow beds are believed to have their 

 equivah'nts in America in the Lower Ilehlerberg, and inasmuch as the 

 Onondaga is below the Helderberg, the tin)e in which the animals lived 

 that have left their remains in the Bloomfiehl sandstone must be still 

 further back. Tlie remains in (piestion indicated a species of the genus 

 OnchuH and two of a genus related to Scaphaspiti of the Pterichthyida;, 

 but different to such an extent as to have impelled Professor Claypole 

 to I'efer them to a new genus called Pahvaspis. 



Next, "a thousand feet lower down, in the middle of the red shale," 

 Professor Claypole found in a thin bed comminuted lish scales or shields 

 resembling in many points those of Palaaspis. 



Further, "live hundred feet lower still, below beds indisputably of 

 Clinton age," in the "well-known iron sandstone," is "a thin layer 

 thickly charged with comminuted scales in much better condition than 

 tiiose in the red shale. With these occurs a spine somewhat like those 

 from the Bloomfield sandstone," which Professor Claypole considered 

 to indicate a new Onchus — the 0. clintoni. 



Professor Claypole asserts that "it is evident that in these fossils we 

 have the most ancient relics of vertebrate life yet known from any part 

 of the world." 



The Professor concludes that, "in thus carrying down the remains of 

 fish almost to the base of the Upper Silurian rocks, it becomes evident 

 that we must seek in some part of our Cambro-Silurian series to tind 

 yet earlier forms. It is not likely that these are the first that existed. 

 Lower beds must be searched." (Aw. N'at, v. 18, pp. 1222-1226.) 



Leptocardians. 



Number of Branchiosiomids. — The lowest type, by all odds, of true 

 Vertebrates is the genus Branchiostoma, a representative at the same 

 time of a peculiar family, order, and class. The first example obtained 

 was described over a century ago by the celebrated Pallas as a Limax, 

 or slug. Since then, several species have been proposed on differences 

 in the number of transverse impressioms representing the limits of what 

 are now called myocommas. These, however, were all ignored by Dr. 

 Giiuther, in 1870, and the species were all " lumped" together under 

 Branchiostoma lanceolatum. " The recent discovery of a second undoubt- 

 edly distinct species of Leptocardian on the coast of Australia [Epi- 

 gonichthijs cultellus], as well as the ac(iuisition of several well-preserved 

 examples," induced Dr. Giiuther " to re examine all the specimens in the 

 British Museum," and he " convinced " himself that the view formerly held 

 byhiin "is incorrect,and that Sundevall was quite right in drawing atten- 



