MUSEUM OF COMPARATIVE ZOOLOGY. 195 



all "roups when sufficient material is studied, are found to fade into one an- 

 other by moderate degrees. In studying the group it will be found, if the 

 student is possessed of material enough and from a sufficiently wide geograph- 

 ical range, that the number of varices, while generally constant, is not an in- 

 variable character; that the same species has many and long, or few and short, 

 spines within the range of its variation, and that the young of nearly related 

 species, especially of the same faunal region, are often indistinguishable one 

 species from another, while the adults present fairly tangible characters. 

 The Murices of the fauna we are considering may be arranged as follows. 



Genus MUKEX Linne. 



Subgenus MUREX s. s. 



This group has been badly handled in Tryon's Manual, the text of which 

 indicates haste and insufficient material, while, the figures are extremely poor 

 and very badly colored. There is no doubt that Tryon was right in reducing 

 the number of species, but a proper reduction can only be made by the exer- 

 cise of great care and the thorough study of a large multitude of specimens. 

 Without committing myself to the distinctness of all the species here included 

 under this group, I can say that they appear to be distinguishable from the 

 rather full material I have been able to examine. 



Murex Beaui Fischer & Bernardi. 

 Murex Beaui F. & B., Journ. de Concliyl., V. p. 295, pi. viii. fig. 1, 1856. 



Habitat. On the Florida Reefs, in 119 fms., Sigsbee; Station 300, at Barba- 

 dos, in 82 fms.; Station 132, in 115 fms., rocky bottom, off Frederikstadt, 

 Santa Cruz; Station 144, on the Saba Bank, in 21 fms.; Station 171, off 

 Guadelupe, in 183 fms., bottom temperatures ranging from 55°.5 to 65°. F. 

 Also at U. S. Fish Commission Stations 2134, south of Cuba, in 254 fms., sand 

 (remarkably fine); and 2402, in 111 fms., mud, between the delta of the 

 Mississippi River and Cedar Keys, Florida. 



This fine and remarkable species was obtained in large numbers at Station 

 2402 of the Fish Commission. It is unquestionably a distinct form, though 

 the very young are hardly to be distinguished from those of M. nodatus and 

 M. clcgans. The adult of the frilled or webbed variety in perfection is a mag- 

 nificent shell. It is curious, however, that the webbing which is so remark- 

 able a character is only found in specimens from deep, clean, and quiet waters. 

 Those from muddy bottom, and all the young ones, show only traces of it, 

 and in the adults there is often not even a trace of it, the varices being as 

 rounded and spinous as if it never had a web. The most prominent and con- 

 stant characters are the height of the spire, deep suture, and peculiarly rounded 

 whorls. 



