THE NAUTILUS. 79 



solid and less translucent, and by the constantly thickened and 

 dilated lip and the presence of the callous deposit. The umbilicus 

 is also wider, being nearly double the diameter of that of the 

 young shells. The aperture is wider and more rounded, that 

 of the young of the above-named species being distinctly sub- 

 angular at the base. As a rule the spire of the young shells is 

 more prominent and the suture deeper, the young shells are 

 also distinctly angular at the periphery. 



Figs. 1, 2, 3, 4, Praticolella campi Clapp and Ferriss. 



Figs. 5, 6, 7, Praticolella griseola (Ph. ) juv. 



STYLOBATES, A WARNING. 



BY WILLIAM HEALEY DALL. 



Some fifteen years ago a colleague interested in Crustacea and 

 whose habit it was to bring me the empty shells from which he 

 had extracted hermit crabs, left on my desk a jar of alcohol 

 containing half a dozen horny objects having the aspect of a 

 large gastropod shell, flexible, yet keeping shape fairly well 

 while moist. The specimens were of a brownish color with 

 beautiful coppery or bronze reflections. Some were torn, but 

 several retained their shape in a nearly perfect manner. Of the 

 most perfect one, the drawings were made which illustrate this 

 note (Plate VI, figs. 8, 9, 10). The specimens recall the large 

 horny Velutina so common in Bering Sea, but of course being 

 nearly three inches in greatest diameter are immensely larger. 

 They were obtained in water between 220 and 436 fathoms deep 

 between Oahu and Molokai islands of the Hawaiian group, by 

 the U. S. Fish Commission steamer Albatross, in 1903. 



The "shells" when collected contained each a hermit crab 

 of large size and served as a pedestal for from one to three large 

 Actinias. 



After due consideration, and the exhibition to my colleagues 

 in the Museum of these singular specimens, I described them as 

 a new genus in the NAUTILUS. * Had there been any marked 



1 Stylobatts aeneus, NAUTILUS. Vol. XVII, No. 6, pp. 61-2, October, 1903. 



