Genus Latirus. 39 1 



the earliest learnt by the student, being of extremely wide 

 distribution, and a handsome, large, brightly variegated 

 form. It forms the type of Swainson's subgeneric Plicatella, 

 based upon characters which it is impossible to maintain : 

 a few forms analogous to this, bring us to L. recurvirostris 

 (Schub. and Wagner), which is a good link with L. gibbulus 

 (GmeL), to which we have already fully alluded as Mont- 

 fort's type of the genus. 



Closely allied to this, is the large and still unique X. 

 ttunens (Carpenter), so grievously misunderstood by Tryon, 

 who thinks it must be a variety of Gracilis (Reeve). Of 

 this, since it has never been figured, I am pleased to be able 

 to give a representation (fig. 14). 



Through L. cariniferus (Lamk) and distinctus (A. Ad.), 

 a very beautiful form, till lately misunderstood, and also 

 figured now for the first time (fig. 3), we are brought to 

 annatus (A. Adams), well pourtrayed in Vol. XV. of the 

 Zoology ''Challenger'' Expedition, (pi. 13, fig. i), and which 

 I have already alluded to, this leading to L. ceratus (Reeve), 

 a very conspicuous W. American species with short canal, and 

 angled whorls with large white concentric nodules, closely 

 allied to L. tuberculatus (Brod), the first of the series 

 hitherto included in Leucozonia (Gray). Through triserialis 

 (Lam.), with rows of sharp nodules ornamenting its whorls, 

 we pass to ocellatus (GmeL), and its elongated form nigellus 

 (Chemnitz). L. cinguliferus (Lam.) is the most variable 

 of the genus ; some forms are angulated approaching rudis 

 and other species, but this variation only strengthens the 

 line of sequence here, and the very smooth rounded L, 

 smaragdulus (L.) and L. leucozonalis (Lamk.) closely show 

 their affinity, A slight hiatus might be thought by some 

 to occur between smaragdulus L. and cingulatus (Lamk.), 

 but I think the shells bear exactly the same principia 

 of character through leucozonalis, as there is an evident 

 sign of a labial tooth, though I do not perceive any such 



