6 Proceedings of the Biological Society of Washington. 



channelled ; the general form Buccinoid ; the surface finely, sharply uni- 

 formly closely spirally striated ; toward the base there are about four sharp 

 distant stronger grooves, the posterior larger than the rest and terminat- 

 ing at the outer lip in a short spur or tooth; siphonal fasciole strong, 

 twisted, keeled; aperture longer than the spire, obovate, with a strong 

 subsutural callus continued into the whorl as a spiral ridge; inner lip and 

 pillar with a smooth arcuate coat of white callus; outer lip with about 

 15 internal lira?; canal short, deep, recurved. Length of shell, 36; of last 

 whorl, 32; of aperture and canal, 26; max. diameter, 21 mm. 



Habitat. — Magdalena Bay, L. Cal. , C. R. Orcutt. U. S. Nat. Mus. Cat. 

 No. 218185. 



It was a surprise to find a third species of Macron on the coast, espe- 

 cially one of such size, and conspicuously distinct from any of the muta- 

 tions of M. aethiops. Two specimens were obtained. 



Phenacolepas magdalena, new species. 



Shell white with a yellowish periostracum, nearly orbicular; anterior 

 slope long, convexly arched, posterior slope shorter, straight ; apex minute, 

 pointed; sculpture of faint close radiating threads uniformly disposed but 

 not crenulating the margin ; these are crossed by low concentric sculp- 

 ture cutting the threads into nodules; interior white, the lateral muscular 

 impressions very broad; length of shell, 15.5; apex in front of posterior 

 edge, 3.5; breadth, 14.5; height, 5.0 mm. 



Habitat.— Magdalena Bay, L. Cal., C. R. Orcutt, U. S. Nat. Mus. Cat. 

 No. 217907. 



This is the first typical species of the genus decribed from West America. 

 Crepidula osculans C. B. Adams, from Panama, afterward named Scu- 

 tella navicelloides by Carpenter, is the only other species of the family on 

 record from this coast, and as that appears to have a sort of ledge inside 

 the posterior edge and a terminal apex (hence the " Crepidula") it can 

 hardly belong to the group typified by P. crenulatus Broderip. 



Marginella calif ornica Tomlin, new var. parallela. 



Shell resemblingthe Californian race of the species but uniformly smaller. 

 The typical form has a faint narrow spiral brown band at the suture, then 

 a pale band, then a broad yellow-brown band, a narrower pale band, a 

 second broad brown band beyond which the shell is pale to the anterior 

 end; — when the shell is not unicolorate. The present variety has the 

 broad brown bands represented by narrow dark brown paired lines with 

 a faint flush of brown between them, giving the shell a very different 

 aspect from the type. 



Length of average californica, 8.5; breadth, 4.0 mm. 

 " " var. parallela, 6.7 " 3.0 " 



Habitat.— Magdalena Bay, L. Cal., C. R. Orcutt. U. S. Nat. Mus. Cat. 

 No. 217843. 



Numerous specimens were collected. 



