184 SHELLS OF LOWER CALIFORNIA— STEARNS. 



examples only from l.U to 1.23 iuches iu length. At this early stage 

 it is nearly impossible to determine under which of the following- spe 

 cific names to place them. While I am inclined to regard them as the 

 juniors of Mcolor, first, from the general aspect leaning toward said 

 species, and. second, because bieolor is the more abundant of the three, 

 there is, nevertheless, a reasonable doubt. We have as closely related 

 forms, P. bieolor Yal., P. brassica Lam., and P. erythrostoma Swains. 



The latter is apparently a pale variety of P. bieolor, of which numerous 

 examples were in my collection and many more have passed through 

 my hands. 



In paragraph 60, on page 559 of Carpenter's "Report (1863) to the 

 British Association," he refers to Sowerby's monograph with com- 

 ments thus "'?=&i6'o/or, var." which it maybe. 1 am inc ined to regard 

 it as a variety of M. {Phyllonotu.s) brassiea. 



MUREX (PHYLLONOTIIS) PKINCEPS, B ro deri p. 



Single example. La Paz (No. 47172, U. S. N. M,). 



The solitary specimen before me is only 1.10 inches in length. The 

 sharpness of sculpture and the elaborate arborescent fringing of the 

 varices in adolescent specimens produce a general effect, which, when 

 compared with heavy adult individuals, is quite likely to mislead those 

 who are not familiar with the West American species in their various 

 stages, and the character of their variation. It is not unlikely that 

 many of the species made by the older authors are really immature 

 varietal forms or geographical varieties. Murex nitidiis, Brod, (Conch. 

 Ills., fig. 4), Sowerby remarks as being " probably a variety of the last 

 [M. prineeps] in a young state." 



The late Thomas Bridges collected numerous specimens of prineeps 

 on the coast of Nicaragua at San Juan del Sur, or in that immediate 

 neighborhood. Prof. C. B. Adams did not report it from Panama in 

 the catalogue of his collection from that place. The Nicaraguan exam- 

 ples, so far as I have observed, differ from those of the Gulf region in 

 the same general way as do the adult specimens of P. radix from 

 Panama from the Gulf forms of the same which the late Dr. Carpenter 

 catalogued in his " Mazatlan Mollusca" as "P. 7iigritus, Meusch.," and 

 in the S. I. check list as •' P. nigritus, Phil." The southern shells of 

 both prineeps and radix are generally more stumi)y and solid. Though 

 some of Prof Adams's specimens of P. radix, Carpenter says in his 

 review* of Adams's catalogue, "are remarkably fine, more nearly 

 resembling the (xulf nigritus than the heavy stumpy shells usually 

 seen, * * * Phyllonotns radix and nigritus graduate into each other 

 almost as freely as the latter does into ambiguus.'''' The last is one of 

 Mr. Reeve's species based on a variety of radix, which, being the older 

 name, must stand, and includes also as synonyms P. nigritus, Phil, of 



* Proc. Zool. Society, London, June, 1863. 



