110 bulletin: museum of comparative zoology. 



in moderate depths, i. e., less than 1000 fa thorns. The bulk of the col- 

 lection from Japan is inside of 300 fathoms ; at a few points only was 

 the dredging carried below 700 fathoms. Consequently this collection, 

 like that of Hawaiian Echini we have under examination, fails to connect 

 the littoral with the deep sea fauna. 



But as regards the so-called continental region, there are some inter- 

 esting points of comparison between the Japanese, the Hawaiian, the 

 Alaskan, and the Panamic faunae. In the Panamic fauna there are 

 but few species which encroach on that region either from the North or 

 the South ; it has a most typical Echinid fauna connecting with the deep 

 water and abyssal region in which we find the Cystechinidae, Urechinidae, 

 Palaeopneustidae, Ananchytidae, and the like ; the nearest relatives of 

 the Panamic Echinid fauna being mainly Indo-Pacific and Pacific species 

 of wide geographical range. We have already called attention to the 

 geographical relation of the Echini collected * in the Hawaiian region, 

 which are in the main Pacific and Indo-Pacific. 



The Japanese collections indicate affinities with some of the Hawaiian 

 Echini. The absence of Cidaris proper and of the widely spread species of 

 Pacific Echinometra, like E. mathaei, pida, and oblonga and of Diadema, 

 is quite striking. We have only Dorocidaris and Stereocidaris common to 

 both the Hawaiian Islands and Japan. Of the Salenidae of Japan, one 

 extends to Hawaii. A new species of Coelopleurus and the presence 

 of Aspidodiadema tonsum indicates the East Indian affinities of Japan. 

 Echinothuriae are common in Japanese waters ; one of the species of 

 Asthenosoma is found in 39 fathoms; Phormosoma from 250 to 918, 

 and Sperosoma from 500 to 176G fathoms. One of the species of Phor- 

 mosoma from Japan is also found at the Hawaiian Islands. The number 

 of species of Sperosoma is remarkable. The species of Japanese Strongy- 

 locentrotus indicate northern Pacific affinities. The species of Temno- 

 pleuridae are either identical with (Prionechinus) or allied to (Genocidaris, 

 Pleurechinus) East Indian species. The occurrence of Hemipedina 

 mirabilis and of Phymosoma crenulare is most interesting. The Japanese 

 collections contain no Hipponoe and only one species of Echinus. It is, 

 however, marked, as is the Hawaiian collection, by the number of its 

 Clypeastroids, especially Laganum of East Indian types, and Scutellidae 

 of Atlantic and northwestern Pacific genera. 



A new Echinolampas has been obtained. The only Pourtalesia is P. 

 laguncula, which, judging from some fragments, grows to a larger size 

 than was previously known. In the deep waters of the Bering Sea and 



i Bull. Mus. Comp. Zool., 1907, Vol. L, No. 8, p. 232. 



