112 MURICID^. 



ment of the adult character. The young Purpura shells retain 

 the embryonic Sinusigera at the summit of the spire for a con- 

 siderable period, but it is eventually lost by erosion. That all 

 the species which have been referred to Sinusigera are larval 

 forms of various species of Purpura does not follow, from this 

 observation ; some of the related genera may be involved. Mr. 

 Arthur Adams has identified another species of Sinusigera with 

 Purpura biserialis, and Mr. Craven thinks that his S. perversa 

 is the young of a Triforis or of some allied genus in Cerithiidse. 



Sinusigera is pelagic, and is encountered in mid-ocean, in 

 tropical seas having feeble currents and where calms prevail. 



Mr. Craven, who has recently monographed the genus, enu- 

 merates twenty species.] 



PuRPUROiDEA, Lycett. 



Distr. — P. nodulata^ Lycett (xliv, 24). Oolite, England. 



Shell turriculated, ventricose ; summit of the spire sharp; 

 whorls convex, with aline of spines or tubercles on. the shoulder ; 

 columella smooth, rounded, excavated in front ; siphonal notch 

 wide, no groove at the posterior junction of lip and columella ; 

 outer lip thin. Fossil. 



This fossil genus has been confounded with Purpurina, d'Orb.: 

 its typical forms appear to be close to Purpura, and the species 

 I figure has some resemblance to the recent P. ehocolatum ; 

 whereas Purpurina is nearly related, apparently, to Cancellaria. 

 The distinctive character from Purpura consists in the close 

 junction of lip and columella posteriorly. 



Lysis, Gabb. 



Distr. — L. duplicosta, Gabb (xliv, 25, 26). Cretaceous, Cali- 

 fornia. 



Stomatiform, very obliqvie ; spire moderate ; whorls costate ; 

 aperture narrow, outer lip simple, inner lip straight, concavely 

 expanded over the wide umbilicus so as to completely cover it. 



Supposed by Gabb to be nearly related to Stomatia ; I have 

 examined authentic specimens, and do not hesitate to refer it to 

 the Purpurse. 



loPAS, H. and A. Adams. 



Distr. — /. sertum, Brug. (xlv, 40). Polynesia. 



Shell ovate, rugose, last whorl large ; spire acuminate ; aper- 

 ture moderate, emarginate and channeled in front ; columellar 

 lip covered wiljh a thin enamel, and with a prominent plait-like 

 callosity at the hind-part; outer lip sinuous, crenate within. 



Vexilla, Swainson. 

 Distr. — 4 sp. Japan, Philippines, Polynesia. V. vexillum, 

 Chemn. (xliv, 21). 



