﻿505 



Cyclolituites. 



This generic .name was given by Remele, who has done more 

 than any other one author to clear up the relations of the different 

 forms of Lituitidae. The species mentioned by him was Cyclolituites 

 apfilanatus, and to this Holm added a new form, Cyclolituites lyn- 

 ceus. His drawings show that Liiuites Lynnensis, Kjerulf,* is a spe- 

 cies of this genus. The drawing made by Barrande of this last is 

 defective in representing the umbilical perforation as too large. 

 Kjerulf 's drawing gives this much smaller. It also gives the lines 

 of growth as bending apically on the first volution and first half of 

 the second volution. They then change to the peculiar forward 

 bend of the Lituidae, and without doubt the aperture changes at 

 this time also to the outline of the adult, so that this is the an- 

 ephebic substage. The hyponomic sinus is narrow and deep, and 

 the crests on the abdominal angles, at first blunt in the anephebic 

 stage, become more prominent in the ephebic stage. The sides 

 have lateral sinuses and probably the dorsum is occupied by a crest. 

 Only the last quarter of the outer volution is free. Schroder 

 doubts whether this is a distinct genus, thinking that it may prove 

 to be the young of true Lituites. 



Cyclolituites Americanus. 



Loc, Gargamelle Cove, Newfoundland. 



This species has a quadragonal whorl with somewhat flattened 

 lateral zones. The abdomen is also depressed, but with a slightly 

 gibbous central zone and linear ventral channels on either side, the 

 abdominal angles appearing, in consequence, as lateral ventral 

 ridges. The lines of growth show that the usual hyponomic sinus 

 was present in the aperture, with sharp, narrow crests on the 

 abdominal angles and broad lateral sinuses on the sides. The lines 

 of growth on the venter are crossed by a secondary system due to 

 the impression of the dorsal lines of an outer whorl, which has 

 been broken off in this specimen. These show that the aperture 

 has a prominent median dorsal crest and that the coiling was close, 

 as in other species of this genus. 



The sutures seen through the thin shell are nearly straight at 

 first, then in the ephebic stage become flexed with very slight 

 lateral lobes and ventral saddles. There are probably slight flex- 



*Vivicsi Christiania, p. 14, 1S65. 



