CLASS GASTROPODA 
51 
in contact or separated, ornamented with longitudinal ribs or thin lamellae, 
often continuous across the suture; periostome entire, thickened, reflected. 
(Tryon, Manual of Conchology .) (Scalaria Lamarck, 1801; Scala 
Humphrey.) 
Bolten did not describe his genus Epitonium, but gave E. scalaria 
Linnaeus as the type. 
Distribution. Greenland, Norway, Britain, Mediterranean, West 
Indies, China, Australia, Pacific, West America. Fossil: Triassic— 
Britain, North America, Chile, India. 
The geographical distribution of the Scalidae agrees in many respects 
with the corals, the number of species being largest in the tropical seas, 
chiefly on the coral islands, and smallest toward the poles. Thus in the 
north polar region are found only four species: Scala gronlandica Perry 
is circumpolar; in the sea of Greenland and Labrador is found besides this 
species Scala (Acirsa ) borealis Beck (S’. eschrichtii Holb.), which is 
not found recent on the European side of the Atlantic Ocean but occurs 
fossil in Sweden (Uddevalla), Ireland. 
In the northern part of the Pacific Ocean are found, besides Scala 
gronlandica; S. wroblewskii Morch ( Scalaria borealis Gould not Beck), 
Scala ochotensis Midd., which may be considered a gigantic S’. borealis 
Beck. In the south polar regions S'. wroblewskii is represented by 5*. aus¬ 
tralis Lam. which resembles it so closely that Dr. Gould considered it 
identical, and for this reason retired his species. S'. borealis Beck, is 
represented by 5. granosa Qet. G., which was considered a Turritella 
on account of the want of ribs. 
On the American Pacific coast line, from Vancouver Island to Upper 
California, Dr. Carpenter has enumerated about eleven species. In the 
tropical region from California to Peru, twenty-six species. On the south 
coast of South America influenced by the polar stream, no species is 
indicated except 5'. magellanica Phil, from the Straits of Magellan. 
The number of living species is probably about 240. 
Subgenus Opalia H. and A. Adams, 1853 1 
Epitonium wroblewskii Morch, 1876 
Plate 31, fig. 5 
Conchologia Iconica, Scalaria. 
Sea. testa crassa, albida pyramidata, latiuscula; anfractibus octo, antice 
obtuse carinatis, ad latera rectiusculis, infra carinam subcomplanatis; 
varicibus paucis, rotundis, indistinctis, inaequalibus, irregularibus, nonnullis 
1 For description of new species received while this volume was in press, see 
Appendix, p. 279. 
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