1890.] NATURAL SCIENCES OF THILADELPHIA. 69 



Separated from Murex recurvirostrls Sowb., by tlie more oval out- 

 line of the first part of the first whorl and by the carina being neai'er 

 the suture in the latter species. It is also more depressed in form 

 than tliat species. 

 Murex brevispina, Lam. (Fig. 5). 



The nucleus consists of one and a half rounded, polished, brownish 

 whorls, of which the first part is a little rounded knob 

 becoming larger and acquiring a sharp spiral carina 

 which encircles its base; the carina begins about mid- 

 way of the whorl, and finally runs into the lowest spi- 

 Fig. 5- ral line of the succeeding whorl. A lateral view shows 

 a rounded outline ; the top of the whorl is rounded ; the tip is a lit- 

 tle depressed. 



There is no decided varix at the end of the embryonic whorl ; the 

 ribs of the succeeding whorls commence abruptly and continue un- 

 til the spinose varices appear upon the third whorl ; there are about 

 ten small, rounded ribs to each whorl. These whorls are shouldered 

 and have a spiral thread below the shoulder ; the sutures are dis- 

 tinct. 



This species is separated from Murex nigrispinosus Reeve, by the 

 whorl being more depressed. 



Murex nigrispinosus, Reeve (Fig. fi)* 



The embryonic nucleus consists of about one and a half polished, 

 rounded whorls; the first is a little rounded knob, and the second is 

 provided with a fine, thread-like carina close to the sut- 

 ure below ; the lateral outline of the whorls descend out- 

 wardly in a curve to the carina, and from the carina to 

 Fig. 6. the suture below it slants inward in a straight line ; the 

 second whorl is but little higher than the first. 



The last apical whorl ends with a thread-like varix, after which 

 they are succeeded by about two unarmed, high, unvarixed, rounded 

 whorls of slow increase, each crossed by thirteen small, rounded, 

 longitudinal ribs and scored by four fine, spiral lines ; the spinose 

 varices appear upon the fourth whorl ; the suture between the first 

 and second embryonic whorls is distinct. 



Separated from M. brevkplna Lam., by its more elongated form 

 and less impressed suture. 



