356 North American Species of Zonites, etc 



cannot judge of the character of the tail from the alcoholic 

 specimens received. 



The jaw is low, wide, slightly arcuate, ends blunt and but 

 little attenuated ; cutting edge Avithout median projection. . 



Lingual membrane long : teeth, 23-1-23, the transverse rows 

 arranged en chevron: centrals small, tricuspid : no lateral teeth : 

 all the side teeth are aculeate marginals (PI. XV, fig. K). 



Macrocyclis Hempliilli, n. sp. 



At Olympia, Oregon, Mr. H. Hemphill collected several speci- 

 mens of a Macrocyclis (pi. XV, fig. M), which appears to be dis- 

 tinct from, though nearly allied to, M. Vancouver ensis. It may 

 be best described by saying that — 



The umbilicus is narrower and not excavated so much — the termination 

 of the last whorl not receding from the umbilicus as in all the forms of 

 Vancouverensis and concava — in all, the whorls are more or less strongly- 

 striated within the umbilicus — often almost ribbed in concava ; not so in this 

 shell — the texture of the shell is glassy like Hyalina, and there is no 

 trace of the microscopic spiral lines found in all the other forms ; — beneath, 

 the last whorl is proportionately wider. The greater diameter is 14 mill. ; 

 lesser, 10 ; height, 5. 



The jaw and lingual dentition are as usual in the genus (See Terr. Moll, 

 of U. S., vol. V, p. 88). I could not distinguish the characters of the cen- 

 tral tooth in this species. 



Titrinizonites latissinius, Lewis. 



I have already, in the Bulletin of the Museum of Comparative 

 Zoology, vol. V, No. 16, p. 333, given a description of this genus 

 and a figure of its lingual dentition. I here add a figure of the 

 animal in motion (pi. XIV, fig. A), not fully extended. The caudal 

 mucus-pore is circular, bordered with a narrow transversely 

 grooved rim ; and when closed is covered completely. When 

 ojien the cover is raised along its longitudinal centre, into a 

 sharp carina, leaving posteriorly when seen from behind, an erect 

 triangular opening. It thus differs from the simple longitudinal 

 slit found in most of the American species of Zonites, such as 

 friabilis, cap nodes, fuliginosus, inornatus, demissus, ligerus, 

 suppressus, the last figured in Terr. Moll., V, fig. 47. Z. laevi- 

 gatas, however, has a nearer approach to the circular pore of 

 Yitrinizonites. 

 The lingual dentition (see Bull. Mus. C. Zool., 1. c.) is nearer 



