126 PHYLOGENY OF FUSUS AND ITS ALLIES. 



CLAVILITHES LONGiEVUS (Solander). 



(Plate XIV, fig. 8; Plate XV, fig. 3-) 

 1766. Mtirex longccvus Solander, Brander's Foss. Hant., figs. 40 and 73, not fig. 93. 



This is the terminal species of this series, paralleling C. scalaris in 

 the Paris Basin Clavilithcs. These two species are generally con- 

 sidered identical, but their independent origin is established on inspec- 

 tion of the early stages of each. 



There has been much confusion as to the true Murcx longccvus of 

 Solander. For a long time the name Fusus longcez'us was applied to 

 the type of the genus Clavilithes, which has been identified by Cossmann 

 with Solander's Murex dcformis. This identification I consider ques- 

 tionable, and I prefer to use Mayer's name C. parisiensis. Sowerby 

 described and figured the fine example of C. solandcri here reproduced 

 as typical Fitsus langcevus. Finally Mons. Cossmann identified 

 Lamarck's Fusus scalaris from the Paris Basin with the typical British 

 C. longccvus (Sol.), calling all by that name. In this he is followed by 

 all recent authors. The differences between these two species have 

 been pointed out and their indepsndent origin noted. Solander's 

 description with omission of unimportant parts is here given, his 

 illustrations are replaced by the more satisfactory photographs of char- 

 acteristic specimens. 



"... testa patulo-caudata Isevi, anfractibus superne coarctatis 

 supra planis, (adultioribus) margine obtuse spinosis." 



"Testa crassiuscula, Isevis, glabra, anfractus supremi transversim 

 striati, omnes supra canali piano distincti, cujus margines in adultioribus 

 obtuse, spinosi uti videre leceat in fig. 40 et 73." 



"Cauda angustata, longitudine ipsius testae." 



"Apertura ovata." 



The protoconch of this species is like that of C. solandcri. 



The conch begins with two rounded, irregular and spirally striate 

 whorls, the second of which has a few vertical undulations. This is 

 the abbreviated rugosus stage. The macrospira stage* which follows 

 immediately upon the rugosus as in C. solandcri, and which in that 

 species characterized most of the whorls of the shell, is in this species 

 very short with a few striations and a shelf, which soon becomes over- 

 hanging and spinose. The length of duration of this stage varies in 

 different specimens, there being sometimes three or fotir volutions in 

 which a shelf exists without a projecting rim. The beautiful regu- 

 larity of the whorls of this stage, so characteristic of C. solandcri, does 

 not appear in this species, the whorls being very irregular. The shelf 

 is also more irregular, the surface not presenting that regular, gradually 



* Whorls like C. macrospira, conical, with sides straight and sloping upwards, 

 and with an abruptly delimited shelf. 



