PHYLOGENY OF FUSUS AND ITS ALLIES. 49 



ening of the upper of the two spirals. This carination becomes very 

 strong, producing a marked central keel. The ribs become gradually 

 weaker and finally disappear, leaving the last two whorls ribless. The 

 angulation of the whorls generally disappears toward the end. Some 

 of the other spirals increase in strength, thus giving the shell a strong 

 spirally striate appearance. 



This species has the form of F. colus or F. longicaudiis with the 

 structure of F. dnpctit-thouarsii. Its close genetic relation to the 

 latter species can not be questioned, though the manner of coiling and 

 the consequent form is very different. Just what relation this species 

 has to F. ineycri Dunker is not clear, as no authentic specimens of the 

 latter have been seen. Judging from the illustrations and descriptions, 

 however, that species is quite distinct from the present one. 



Three specimens of this species have been seen, and all are labeled 

 as coming from the East Indies. They were all identified, however, 

 with oriental species of Fusiis, and the localities given can not be con- 

 sidered as quite trustworthy under the circumstances. Should the 

 localities be correct, this species would constitute an important con- 

 necting link between the east- and west-Pacific Fusi. 



It will readily be seen that the variations found in F. dnpctit- 

 thouarsii may again occur in this species. They have not been found, 

 it is true, since the number of specimens examined is so very small, but 

 it is easy to predict that in a large collection of specimens of this species 

 ail the normal varieties of the coins series will be paralleled. 



Locality: (?) East Indies (M. C. Z. 940, B. S. 223). The locality 

 is probably erroneous, the specimens having been labeled F. longicauda. 



FUSUS MEYERI Dunker. 



1869. fusus meyeri Duxker, Novitates, p. 127, tab. 43, figs, i, 2. 

 1881. Fusus meyeri Tryon, Manual, p. 63, pi. 38, fig. 156. 



The essential characteristics of this species are the following, ac- 

 cording to Dunker. The slender shell consists of ten to twelve convex 

 volutions which are uniformly white and separated by a deep suture. 

 The upper whorls are strongly ribbed and noduled, but these ribs 

 become weaker in the later whorls, and disappear wholly on the last 

 one. Sharp raised spirals with finer ones between characterize the 

 surface. Dunker states that this species comes nearest to /*". longi- 

 caudiis, referring undoubtedly to the form. 



A specimen without locality (M. C. Z. 914) is referred to this 

 species, though this reference may be questioned. It is a slender variety 

 of F. dnpctit-tJionarsii, aj^parently standing between that species and the 

 one described above as var. irregularis. The early whorls show the 

 angular bicarinate stage merging later into an angular bicarinate ribless 

 stage, which later is replaced by a unicarinate stage, in which the ribs 



