PATULA-ANGUISPIRA. 115 



remarkable for their polymorphism. The species may be divided 

 into two sections : the first, or typical ANGUISPIRA, proposed for 

 alternate*,, including also mordax and cumber landiana (which are 

 hardly more than extreme forms of alternata), is characterized by a 

 flammulate, regularly striated shell, by the oviparous mode of repro- 

 duction, etc., and is not far removed from the section Discus. The 

 second division or section has a unicolored or spirally banded shell, 

 irregularly striated or ribbed, often spirally striated, and gives birth 

 to living young. The young usually have spiral rows of hairs, and 

 resemble considerably some New Zealand Patuloid forms, which 

 probably reproduce in the same manner. In the species of this 

 division, the characters of sculpture, form and color, and to a less 

 degree of the soft parts, vary to an extent inconceivable to those 

 who have not actually seen the shells. It may now be demonstrated 

 that the forms described as H. strigosa, cooperi, idahoensis, hemphilli, 

 haydeni, etc., are connected by such a multitude of intermediate 

 forms that it is absolutely impossible, by the most acute analysis, to 

 draw lines of demarcation between them. It is even impossible to 

 classify many specimens if we attempt only the division into three 

 series, as is done below. 



The literature of these varieties and forms will be found in the 

 NAUTILUS for 1890, and in Binney's Second (1886), Third (1890), 

 and Fourth (1892), Supplements to Terr. Moll. V. The classifica- 

 tion is mainly that given by Binney (I. c.) 

 P. STRIGOSA Gould. (Vol. Ill, p. 56.) 



(1) Radially ribbed forms (P. idahoensis Newc.) 

 Var. IDAHOENSIS Newc. 



The type of this group of forms is well represented by figs. 29, 30, 

 31 of pi. 10, in Vol. Ill, representing the typical Patula idahoensis. 

 I have not seen intermediate forms absolutely uniting this to var. 

 binneyi (below), but the unbridged space between the two is so nar- 

 row that perfectly intermediate examples may be confidently 

 expected. 

 Var. NEWCOMBI Hemphill. PI. 41, fig. 88 (typical), figs. 89, 90 



(var.) 



This is perhaps the most extraordinary of the entire strigosa 

 series. The shells were collected near Ogden, Utah, at an altitude 

 of 4500 feet. In the typical newcombi (fig. 88) the body-whorl is 

 rounded but there is a keel sketched around it ; the surface has 



