40 PHYLOGENY OF FUSUS AND ITS ALLIES. 



two to five similar fine revolving lines. All these finer spirals show 

 best on the periostracum, where they are accentuated by fine bristles, 

 which arise at their junction with the growth lines. 



The color of the shell is white, that of the periostracum a brownish 

 olive when dry. 



In a number of the West Indian specimens studied it was found that 

 the keel and nodes are never developed, in the most accelerated indi- 

 viduals. The whorls remain round, with perhaps only a slight ac- 

 centuation of the median primary spiral. The ribs continue some- 

 times into early maturity, but in all these accelerated individuals the 

 last whorls are free from ribs, and without a keel. The whole tendency 

 in the development of these shells is towards the dropping out of the 

 inherited angular stage, and passing from a round-whorled and ribbed to 

 a round-whorled and ribless stage. This accomplished, the longicaudns 

 stage is reached. 



F. clostcr was described from a specimen obtained from the Isle of 

 Margarita. The illustration, however, which Philippi gives is not 

 characteristic of the species as represented by large collections from 

 that locality. The chief points of difference between this species and 

 F. distans are given by Philippi in the following words : "Von F. distans 

 Lamk. unterscheidet sich gegenwartige Art durch den ganzlichen 

 Mangel der Kante in der Mitte der Windungen und durch eine 

 verhaltnissmassig weit langere Spira" (vol. 3, p. 115). Among the 

 specimens studied several were more slender than the Philippine species, 

 but none as slender as the one figured by Philippi has been observed. 

 If this unusually slender appearance is not due to a wrong perspective 

 in Philippi's figure it is possible that his figure represents a specimen 

 of F. pcrplexns substituted by mistake. His figure may very well 

 stand for the accelerated variety of that species. 



Locality: Isle of Margarita, West Indies (Acad. Sci., ]\I. C. Z. 

 919?; 921? Nat. Mus. 54474). 



The specimens of the closter type from the Red Sea in the coll. Am. 

 Mus. Nat. Hist, are probably of independent origin. 



5. THE FUSUS LONGISSIMUS SERIES. 



FUSUS LONGISSIMUS (Gmelin) Lamk. 



1780. Fusus magnns, etc., Chemnitz, Conch. Cat., T. 4, p. 177, pi. 144, fig. 1339. 



1780. Fusus longissiiniis, etc., Chemnitz, do., p. 183, pi. 145, fig. 1344. 



1788. Murex canditus Gmelin and Murex longissimus Gmelin, Linne, Syst. 



Nat, edit. 13, T. i, pars VI, Vermes test., p. 3556. 

 1822. Fusus longissimus Lamarck, An. sans, vers., t. VII, p. 122. 

 1842. Fusus longissimus Kiener, Iconographie, p. 3, pi. 2, fig. i. 

 1847. Fusus longissimus Reeve, Iconica, sp. 4. 



(If Gmelin is regarded as the authority for the species and not 

 Chemnitz, who was not binominal, canditus should be the name of the 

 species, as that precedes longissimus. Authors generally have followed 

 Lamarck, however.) 



