A MONOGRAPH OF THE EXISTING 

 CRINOIDS 



By Austin Hobart Clark and Ailsa McGown Clakk 



Order COMATULIDA A. H. Clark (continued) 

 Suborder OLIGOPHREATA A. H. Clark (continued) 



Since the preceding part of this monograph was written there has been established 

 the new superfamily Notocrinida, including the family Notocrinidae and the new 

 family Aporometridae. This new superfamily is most logically placed between the 

 superfamilies Mariametrida and Tropiometrida and therefore must be considered before 

 the suborder Macrophrcata. 



Superfamily NOTOCRINIDA Gisldn (emended) 



Notocrinida Gisl^n, Zool. Bidrag Uppsala, vol. 9, 1924, pp. 231, 237, 238. — H. L. Clark, Mem. Mus. 

 Comp. Zool., vol. 55, 1938, p. 42. 



Diagnosis. — A superfamily of the suborder Oligophreata in which the arms and 

 pinnules are rounded dorsaUy; the cirri are arranged in 10 regular colimms on a more or 

 less conical (Notocrinidae) or nearly discoidal (Aporometridae) centrodorsal; and the 

 disk is plated. The included species are viviparous. 



Geographical range. — Antarctic regions and southern Australia, north to Mannmg 

 river, New South Wales, and Fremantle, Western Australia. 



Bathymetrical range. — From the shore line down to 640 (?731) meters. 



Thermal range. — From about 21° C. down to —1.84° C. 



Remarks. — The superfamily Notocrinida was proposed since the publication of 

 Part 3 of the present work. This superfamily includes two groups, the systematic posi- 

 tions of which have been variously understood by Prof. F. Jeffrey Bell, Dr. Hubert 

 Lyman Clark, Dr. Th. Mortensen, Prof. Torsten Gislen, and the author. 



Professor Bell described the first known species, Aiitedon wilsoni, which he assumed 

 was closely related to Perometra picsilla (Antedonidae; PerometrLnae) . The next 

 species was described by Dr. H. L. Clark under the name of Himerometra paedophora. 

 Both of these species were considered by the author as the young of Ptilometra. 



Dr. Mortensen in his discussion of the systematic position of Notocrinus said that 

 it is at once evident that it can not belong to the Oligophreata. It is decidedlj'' of the 

 macrophreate type. Of the three families of the Macrophreata, Atelecrinidae, Ante- 

 donidae, and Pentametrocrinidae, the last, according to Mortensen, is at once excluded. 

 The presence of basals recalls the Atelecrinidae, in which family similar small basals 

 occur in Atopocrinus. But Mortensen noted that the peculiar character of the cirrus 



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