Verrill, Notes on Jladlata. 515 



vesicles, which sometimes liave ii radiated structure and may, perhaps, 

 indicate the position of a second form of polyps ; in other cases (as in 

 Allopora) there are also minute pores or openings with a raised border 

 scattered between the ordinary cells, which appear to represent a sec- 

 ond more rudimentary form of polyps. Therefore it is probable that 

 in this family the polyps are dimorphous, as in Pennatulacea and some 

 Alcyonacea, and in many Ilydroids, but the soft parts have not yet been 

 described. The polyp-cells are small, generally filled up below by a 

 solid deposit, sometimes also partially filled up and more or less obliter- 

 ated by the thickening of the septa and the union of their inner edges, 

 thus separating the interseptal chambers from the central part of the 

 cell, and in some genera, like Distichipora and Errina, nearly or 

 quite obliterating some of the chambers. The se})ta are mostly nar- 

 row, equal or nearly so, in one to three cycles, in some instances only 

 four to six, most frequently twelve, the third cycle, when present, rudi- 

 mentary. Columella generally styliform, sometimes wanting. 



This family, as now constituted, includes the following genera : — 

 Axohella E. and H. ; Gryptohelia E. and H. ; Endohelia E. and H. ; 

 Cydopora Verrill ; Stylaster Gi-ay ; Allopora Ehr. ; Distichipora 

 Lamarck; Errina Gray. 



In the works of Edwards and Haime the genus Distichipora was 

 placed, with other still doubtful forms, in the " incerta sedes " at the 

 end of the list of genera. In the final work* it is placed in an appen- 

 dix and doubt is expressed whether it may not belong to the Alcyona- 

 ria, rather than to the Madreporaria, while Errina is entirely omitted. 

 The writer first explained the structure of these genera and referred 

 them to their true position near Stylaster^ in the Bulletin of the Mu- 

 seum of Comparative Zoology, No. 3, jx 46, 1864. Mr. Pourtales, 

 who has recently discovered and described several new and very 

 interesting members of this group, fully confirmed this conclusion in 

 later numbers of the Bulletin.f He has also suggested that the group 

 should form a distinct family, — an opinion in which we fully concur. 



Many of the species of this family seem to be confined to great 

 depths, where they form a considerable poition of the coral faunsp, 

 and yet there are, also, shallow-water species both in the Atlantic and 

 Pacific. When deeper dredgings shall have been made on the west 

 coast of America, additional genera and species may be expected, but 

 at present two species of the genus Allopora are the only known 

 representatives of the family on the whole coast. 



* Coralliaires, vol. iii, p. 450, 1860. 



f No. 6, pp. 116, 117, 1867 ; No. 7, p. 136, 1868. 



