. Bulletin - New York State Museum. Science. BEEKxMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 457. Since Schroder has shown that Whitfield based his description partly upon the specimens Avhich are now the types of E . r o - t n n d u s, we must accept Schroder's diagnosis, based on Whitfield's first figure, as the only valid one. Since however Schroder had not the tvpe specimen in hand and Whitfield has figured neither longitudinal nor transverse sections of the type it is evident that that portion of Schroder's diagnosis which gives the interior characters can not be reliable. It is clea
. Bulletin - New York State Museum. Science. BEEKxMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 457. Since Schroder has shown that Whitfield based his description partly upon the specimens Avhich are now the types of E . r o - t n n d u s, we must accept Schroder's diagnosis, based on Whitfield's first figure, as the only valid one. Since however Schroder had not the tvpe specimen in hand and Whitfield has figured neither longitudinal nor transverse sections of the type it is evident that that portion of Schroder's diagnosis which gives the interior characters can not be reliable. It is clearly copied from Whitfield's de- scription, which in its turn refers again to the smaller specimen, or the present E. r o t u n d u s . It is probably on this ac- count that Hyatt queries the correctness of Schroder's diagnosis [1894, p. 442]. Be- sides the internal characters, the material from Valcour furnishes other additional diagnostic characters not obtainable from the type specimen. We have for these rea- sons and also because Schroder's diagnosis is probably not everywhere readily acces- sible inserted here a full description of the species drawn from Professor Whitfield's specimen, and from our material obtained at Valcour. Description. Conch a rather closely coiled nautilicone up to gerontic age, when the living chamber becomes free, but does not straighten and only unfolds into an arc with a larger radius, 4-5 volutions, giv- ing the conch a diameter of 170 mm. Volu- tions slightly compressed, elliptic in section in the ephebic stage and subcircular in the nepionic and neanic stages [see text fig. 21] ; ratio of hight to width of volution where the latter has a hight of 27 mm approximately as 9:8 and where it has a hight of 40 mm as 10:8, No lateral zones differentiated; a ventral zone indicated by a slight flattening; the impressed (dorsal) zone slight but continuous upon the free geron- tic volution ("persistent impressed zone"). Growth of conch quite rapi
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