" ZOOLOGY. 623 



wliile engaged "on work on the palseoutology of Pennsylvania." First, 

 be found in wbat he calls the " Bloomtield 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 

 equivalents in America in the Lower Helderberg, and inasmuch as the 

 Onondaga is below the Helderberg, the time in which the animals lived 

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

 further back. The remains in question indicated a species of the genus 

 OnchuH and two of a genus related to Scaphaspis of the Pterichthyidae, 

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

 to refer them to a new genus called Palceaspis. 



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

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

 resembling in many i)oints those of Palceaspis. 



Further, "five 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 

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

 from the Bloomfield sandstone," which Professor Claypole considered 

 to indicate a new Onchns — the 0. cl'mtoni. 



Professor Clayi^ole 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 

 fihh 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 find 

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

 Lower beds must be searched." (Am. Nat., v. 18, pp. 1222-1226.) 



Leptocardians. 



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

 Vertebrates is the genus BrancMostoma, a representative at the same 

 time of a i^eculiar 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 difi'erences 

 in the number of transverse impressions representing the limits of what 

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

 Giinther, in 1S70, and the species were all "lumped" together under 

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

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

 (jonichthys cultellus]^ as well as the acquisitiou of several well-preserved 

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

 British Museum,"and he" convinced" himself thattheviewformerly held 

 by him " is incorrect, and that Suudcvall was quite right in drawing atteu* 



