DIplograptus.] 



SPONGES, GRAPTOLITES, CORALS. 



81 



f7 to -jV mm - i n si ze > aQ d are i n direct contact throughout, no interstitial tissue of 

 any kind being developed. The tubes are irregular in form, with thin, often undu- 

 lated walls, which are not pierced by any apertures or pores, but are often crossed 

 by more or fewer transverse partitions or "tabulse." Very commonly the tubes 

 exhibit more or fewer inwardly directed partitions, which extend to a greater or 

 less distance into the cavity of the tube, and are the result of the cleavage or ' fission ' 

 of the tubes." 



Formation and locality. Rare in the Trenton shales near Cannon Falls, Minnesota ; Frankfort, 

 Kentucky and Nashville, Tennessee. In the Black River group at Pauquette Rapids on the Ottawa river, 

 and island of Montreal, Canada. In division L, Newfoundland. Dr. Nicholson says it has also been 

 found in Great Britain and Russia. 



Mus. Reg. No. 8055. 



Sub-Kingdom CCELENTERAT A. 



Class HYDROZOA. 



Sub-class GRAPTOLITOIDEA. 

 Family DIPLOGRAPTID^E, Lapworth. 

 DIPLOGRAPTUS PRISTIS ? (Hisinger) Hall. 





FIG. 2. 



1837. Prinotus pristis HISINGEK. Lethaea Suecica, p. 114, pi. 35, ilg. 5. 



1847. Graptolithvs pristis HALL. Paleontology of New York, vol. i, p. 265, pi. 72, figs. la-Is. 



1863. Graptolithus pristis BILLINGS. Geology of Canada, p. 200, flg. 195. 



18(i5. Graptolithus (Diplograptus) pristis HALL. Canadian Organic Remains, dec. ii, p. 15, flg. 3b: 



p. 109, flgs. 21, 30. 

 1867. Graptolithus (Diplograptus) pristis HALL. Twentieth Rep. N. Y. State Cab. Nat. Hist, pp, 



182, 205, flgs. 22, 32. 

 1875. Diplograptus pristis NICHOLSON. Pala'ontology of the Province of Ontario, p. 38. 



Prof. Hall gives Hisinger's description of this species as follows : " Linear, 

 straight, scarcely a line broad, compressed ; rachis central, capillary ; both sides 

 with broad acute teeth" (op.cit. 1847). 



