84 GENERIC ALLIANCES. 
GENERIC ALLIANCES. 
LaMaRcK separated the genus Nassa from the parent Buccinum, 
Tinn., in 1792. “This genus is not admitted by all conchologists 
as a necessary separation from the Linnean genus Buccinum, and, 
in fact, Lamarck subsequently re-united them, without assigning 
any reason fer so doing.”—S. Wood’s “ Mollusca from the Crag,” 
vol. 1, p. 28. 
In the Nassa reticosa, J. Sow., variety rugosa, we have a shell 
possessing the characters of Buccinum. Several of the Nass are 
simply small forms of their large parents; the N. pyramidalis, 
A. Ad., is a small form of Buccinum undatum, Linn., var. glaciale ; 
N. undata, Marr., was so named in consequence of its resemblance 
to B, undatum, and many other representative forms might be given 
by way of illustrating the alliances of the two supposed genera. 
The Desmoulea abbreviata, Chem., is very nearly allied to the 
Nassa pupa and N. conglobata, Broc., both of which pass by means 
of N. obliquata, Broc., into N. mutabilis, Linn. One of the most 
variable shells in the Buccinum group is the Phos senticosus, Linn.; 
the broad and short forms are closely allied to some of the shells 
in the genus Nassa. In the animal of Phos one of the principal 
differences pointed out is the foot tapering into a filament—not a 
very satisfactory character, I must say, after the statement with 
regard to the same part of the animal of Nassa being bifid. Another 
shell, figured in D’Orbigny’s Cuba” under the name of Cancellaria 
candei, D’Orb., is an intermediate form between Nassa and Phos. 
The Strongylocera, Morch., is a badly defined group, including such 
shells as the Phos textilinus, Sow., and Buccinum costatum, Quoy 
and Gaim., ‘Voy. I’ Ast.,” pl. 30, f. 17, 18, &c. 
Bullia is closely allied to Nassa; we find a great resemblance 
existing between the small forms of the B. semiflammea, Reeve, 
and the shells placed by H. and A. Adams as Aciculina, a sub- 
division of the genus Nassa; the two varieties, Bullia polita, Lam., 
and semiplicata, Gray, are related to the N. trifasciata, Gmel., and 
the narrow forms of N. glans, Linn. ; another shell named and figured 
by Reeve as the B. truncata, is much nearer the shells in the genus 
