1890.] NATURAL SCIENCES OF PHILADELPHIA. 71 



nodulous until the spinose varices ap])ear upou the fourth whorl ; 

 there are about thirteen small, rounded ribs to each whorl, crossed 

 ])v four spiral threads; the suture is impressed. 



Separated from Murex rectirostris Sowh., l)y the more rounded 

 outline of the first part of the embryonic whorl and the absence of 

 the shoulder upon the second i)art. 

 Murex similis, Sowb. (Fig. 10). 



The nucleus c(msists of one and a half whitish, 

 smooth, rounded whorls; the lateral outline shows a 

 rounded appearance ; the first i)art of the whorl is a 

 little rounded knob. 

 Fig. lo. A sharp and well-defined varix appears at the end 



of the embryonic whorl, and this is followed by a number of high, 

 rounded ribs, which cease at the appearance of the spinose varices 

 upon the fourth whorl ; there are thirteen of these ribs to each whorl 

 crossed by four fine, spiral lines. 



This species is separated from Murex ternispina Lam., by the ab- 

 sence of the thread-like carina near the ending of the embryonic 

 whorl. The sutures are not so deep as in the latter species.. 

 Murex tryoni, Hidalgo. 



Upon examining this shell I was much surprised to find that it 

 had an apex identical with that of the preceding species. This may 

 prove to be but a variety of 31. similis as was thought by Dr. Dall. 

 Murex cailleti, Petit. 



The embryonic apex of this species is identical with both simi- 

 lis and tryoni. I have not been able, through lack of perfect speci- 

 mens, to examine the apex of the typical motaciUa of ('hemnitz. 

 Murex aduncospinosus, Beck. (Fig. 11). 



The nucleus consists of 2? blunt, conical, glossy, fulvus, flat-sided 



Awdiorls, which increase regularly from the apex ; the 

 last whorl is margined below by a very fine thread just 

 at the suture ; the lateral outline shows a cone of about 

 Fig. II. two regularly increasing whorls, of which the second is 

 twice as large as the first. 



There is a rounded varix of considerable size at the end of the last 

 embryonic whorl after which they are nodulously ribbed until the 

 hollow spines appear upon the sixth whorl ; these are crossed by 

 four fine, thread-like spiral lines ; the sutures of the embryonic 



