THE NAUTILUS. 93 



of them reaching it while still young. * * Ft/siis m/iis, the type 

 of the genus, is itself a regressively accelerated type, in which the 

 characteristic acmatic features have nearly disappeared in the adult. 

 Excessive degradational acceleration is seen in ('t/rtx/t/s, Clavilithes 

 and similar genera." 



In the eocene of the Gulf States there is a group of shells having 

 the form of a true Fusus but with a protocoiich similar to many 

 suHfies usually referred to Pleurotoma. For such shells the new 



I ti 



genus Fahifnsus is proposed. Type : Fusus meyeri Aldrich 

 (not Dunker). 1 beg to differ with the author in using F. meyeri, 

 Aldr. Fusus meyeri, being preoccupied, becomes a synonym and re- 

 mains a synonym ; the name of F. ottonis Aldr. proposed in its stead 

 should be adopted. 



For two forms (Fusus quercollis and F. rugatus) from the lower 

 eocene of Alabama, the name of Fulyurojnsus is proposed. The 

 protoconch is Fulguroid. The new .generic name of Heilprinin is 

 "iven to a number of recent and late tertiary fusoid shells from the 



O * 



Antillean region and Florida. " They differ from Fusus in the very 

 remarkable, strongly accelerated protoconch, which is throughout its 

 greater portion crossed by riblets." Type : Fttsus caloosaeiisis 

 Heilp. 



Under the head of Phylogerontic Fusidre is placed the peculiar 

 Cyrtulus serotinus Hinds. Its genetic relation to Clavilithes is dis- 

 puted ; in its young stages it is a typical Fusus, but in the adult the 

 whorls become thick and loosely wrapped about one another ; this 

 type of structure is designated as Melongenoid. To the eocene 

 forms which most closely resemble Uyrtulus, the new generic name 

 of Ctacellofusus is given. " Genotype : GlaveUofusus spiratus sp. 

 nov." Under this genus are described three new species from the 

 Paris Basin, forms which are considered by most authors to be only 

 variations of the variable ClavililheS longsevus Lam. The author 

 seems to have had very few specimens showing the protoconch on 

 which to base such novel conclusions. Under the genus Cluvi- 

 lithes several new species are described, including C. solanderi, based 

 on the Murex longsevtis Solander (in part) and including specimens 

 figured by Sowerby. (Mineral Conch. I, 141, tab. 63, f. 1, 1812). 

 It may be of interest to know that this identical specimen is in the 

 collection of the Academy of Natural Sciences, Philadelphia. It was 

 presented to the Academy by Dr. Thos. B. Wilson, who purchased it 



