23 



LiTUITES IMPBRATOR. (N. Sp.) 



Description. — Very large, the coiled portion alone being lOJ inches 

 across. The first two whorls are 2J inches and the first three 4J inches 

 across. The first three are coiled in contact ; after which the whorls 

 begin to separate, and at the completion of the fourth are distant about 

 i of an inch. The last whorl is then produced nearly in a straight line 

 for about 2 inches, after which (in the only specimen collected) it is not 

 preserved. The dorso- ventral diameter of the tube where broken off is 

 almost 4J inches. The distances of the septa vary greatly. In the com- 

 mencement of the third whorl there are three in one inch, but they gradu- 

 ally become more distant until at the end of this whorl there are only two 

 in one inch. The distance then diminishes, and at the middle of the 

 fourth whorl there are four ui one inch. (These measurements relate to 

 the outer side.) Beyond this they are not seen, but the siphuncle is pre- 

 served to the end of the fourth whorl, and shows the traces of nine septa 

 in the last inch. The siphuncle is exposed in the specimen in two places, 

 both in the fourth whorl. In the first quarter of the length of this whorl 

 it is concealed. In the second quarter it is laid bare for a length of Sc- 

 inches. It is here 4 lines in diameter, and its position is, as nearly as can 

 be, central. In the last quarter of the whorl there is another exposure of 

 about 4 inches, its diameter being five lines, and its position, where last 

 seen, 2^ inches from the ventral or outer margin, and IJ inch from the 

 dorsal or inner margin. The position therefore of the siphuncle in this 

 species varies in different parts of the same individual. This agrees with 

 Earrande's observations on Orilioceras mimdum, in which the siphuncle 

 passes from one side to the other in such a maner that ten or twelve 

 species might be made out of different fragments of the same individual, 

 specimen, provided the position of the siphon were alone to be taken into 

 account and the species described by different observers without a know- 

 ledge of their connection.* 



The only specimen collected is firmly imbedded in the limestone matrix, 

 and is worn away so as to exhibit a complete section along the plane of 

 the coil, showing all the whorls and the siphuncle as above mentioned. 

 The character of the surface cannot thus be observed. But judging from 

 the appearance of the shell as seen in the section the last whorl is crossed 

 by wide shallow undulations, but no traces of these can be seen on the inner 

 whorls, where the shell is also visible. 



Locality and Formation. — Phillipsburg in the County of Missisquoi, 

 Canada East. In the upper part of the Calciferous Sandrocfc. 



Collector. — Dr. P. J. Farnsworth. 



* Bakbande. In Bronn's Neues Jahrbuch, 1859, p. 608. 



