﻿160 DEVONIAN FAUNA. 



for about one-sixth of their length, after which they again become perpendicular to 

 the suture until near the base, when they again sweep rapidly backwards until they 

 are merged in the fold of the inner lip. Minor ornamentation consisting of fine 

 irregular strige following the course of the larger markings. Surface of upper 

 whorls with similar ridges, truncated halfway down by the suture-line of the 

 succeeding whorl. 



Size. — A specimen from Wolborough measures about 70 mm. in height and 

 about 40 mm. in width. 



Localities. — From Lummaton there are two well-preserved fragments in 

 my Collection. From Wolborough there are five specimens in Mr. Vicary's 

 Collection ; five in the Museum of Practical Geology ; five in the Torquay Museum ; 

 one in the Woodwardian Museum ; and one in the British Museum. In the 

 Torquay Museum is a small specimen from an unknown locality which is replaced 

 by beekite. 



Remarks. — This fine species does not appear to be uncommon. It is repre- 

 sented in museums, as seen above, by many fine specimens, which show most of 

 its details, although they are rarely sufficiently perfect to give its exact dimensions. 

 The outer lip is in every case defective or destroyed. They are often crushed or 

 contorted, and this is probably due to the thinness of the shell-walls. These 

 specimens appear to present some variability in the length of the spire and the 

 number of the whorls, but their general facies is so similar that there can be little 

 doubt that they all belong to one species. 



Two of Phillips's figured specimens are among those in the Museum of 

 Practical Geology. One of these is the type of his species M. elongata, and this 

 at first sight appears to differ from the rest in being a more spindle-shaped shell 

 with a much longer columella. These differences, however, are deceptive, being 

 entirely due to the imperfection of the specimen. It has been longitudinally 

 fractured, as indicated in his figure, and this fracture was caused by the shell 

 having been subjected to lateral crushing, which has given the appearance of 

 greater length to the shell and of greater obliquity of the suture-line, as well as 

 bringing the inner lip into undue prominence. Moreover, the outer lip has been 

 broken off straight down the perpendicular from the apex, so as to make it simu- 

 late a long siphuncle, whereas in all likelihood there was originally no elongation 

 of the base at all. In fact, several of the other specimens, which are crushed, look 

 on the one side exactly like this shell, while on the other side they agree exactly 

 with Phillips's figure of his M. arculata, except that they are even broader. Hence 

 it is clear that the species M. elongata cannot be retained, but must be reunited to 

 the present form. It may be noted that Phillips's figure is rather larger than 

 life-size. 



The other figured specimen in the same Museum is Phillips's type of 



