PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 801 



3.39 C.; fine gray sand and globigerinae ; October 20, 1906 [A. H. Clark, 1907] (15, 

 U.S.N.M., 35916). 



Albatross station 5082; near Suruga Gulf; Omai Saki light bearing N. 22 E., 33 

 miles distant Gat. 3405'00" N., long. 137 59'00"E.); 1210 meters; temperature 3.17 

 C.; green mud, fine sand and globigerinae; October 20, 1906 [A. H. Clark, 1907] (2, 

 U.S.N.M., 35923). 



Albatross station 5079; near Suruga Gulf; Omai Saki light bearing N. 29 E., 24 

 miles distant (lat. 3415'00" N., long. 13800'00" E.); 868-923 meters; temperature 

 3.95 C.; pebbles; October 19, 1906 [A. H. Clark, 1907] (2, U.S.N.M., 35917). 



Challenger station 235; south of Japan Gat. 3407' N., long. 13800' E.); 1033 

 meters; temperature 3.39 C.; green mud; June 4, 1875 [P. H. Carpenter, 1882, 1888; 

 A. H. Clark, 1913] (2, B.M.). Type locality. 



Geographical range. From the Lesser Sunda Islands northward to southern Japan, 

 as far eastward as Tokyo Bay. 



Bathymetrical range. From 254 to 1210 meters; the average of 17 records is 872 

 meters. 



Thermal range. From 3.05 C. to 11.61 C., but all but two of the records are 

 below 6 C. The average of the 12 records is 5.20 C.; the average of all the records 

 except the two highest is 4.04 C. 



Remarks. Carpenter remarked that it was with some hesitation that he separated 

 japonicus from semperi; but japonicus is altogether larger and more massive than 

 semperi, with a larger and more distinctly conical centrodorsal and more numerous 

 cirri. The first brachials have larger muscle plates for articulation with the radials, 

 and are more trapezoidal in outline. As the second brachials are relatively longer 

 than those of semperi and at the same time more trapezoidal hi form, the base of each 

 arm is considerably constricted at the junction of its first two brachials. He noted that 

 the general proportions of the remaining brachials and of the pinnules appeared to be 

 much the same in the two types, excepting that in the smaller semperi the segments 

 of the lower pinnules are rather longer in proportion to their width than in japonicus. 



In his key to the species of the genus " Eudiocrinus" Carpenter separated these 

 two species on the basis of the plated disk and nearly oblong first brachials of semperi as 

 contrasted with the naked disk and trapezoidal first brachials of japonicus. 



In some individuals the plating of the disk is far more conspicuous than in others. 

 For instance, it is very noticeable in the rather large specimen from Albatross station 

 5661, which has a conical centrodorsal and is in every other way a typical japonicus. But 

 on close examination I find a plating quite resembling that described for semperi in some 

 of the specimens of japonicus dredged by the Albatross off southern Japan. 



[NOTE BY A.M.C.] Mr. Clark concluded from this that japonicus and semperi are 

 synonymous. However, having examined the type specimens of both species and 

 found that those of semperi have only about 15 cirrus sockets as opposed to 35 and 40 in 

 japonicus, where the centrodorsal itself is much larger though the lengths of the proximal 

 brachials are the same, I cannot agree that they represent the same species. I am 

 therefore restoring japonicus as a valid species. On biogeographical grounds also the 

 identity of the two is unlikely. 



