E. OWENI. — GEN. CHARACTEKS. 209 



sometimes, however, spicules of quite inconspicuous length may 

 project out here and there. The line of insertion of the cuff, 

 i. e., the juncture-line of the lateral parietes with the sieve- 

 plate, as seen from the side, is generally irregularl}^ wavy. 



The parietal oscula measure 2 mm. or less in diameter. 

 They are arranged on the wdiole with tolerable regularity in 

 longitudinal and transverse rows (PL VI, figs. 1, 4). Here and 

 there, this regularity is subject to disturbances, conditioned in a 

 measure by the development of, and the course taken by, the 

 parietal ledges. Thus, by the sides of an obliquely running ledge 

 it is usual to fiud the oscula arranged in rows running parallel 

 to it. In some specimens (e. g., Spec. Q, shown in figs. 2 & 3), 

 the distribution of the oscula may be said to be generally rather 

 irregular, which fact may stand in relation to the wide-spread 

 occurrence of ridge-like elevations over nearly all of the external 

 surface. 



With regard to the appearance of the parietes on the inter- 

 nal side and to the arrangement of beams in the skeletal frame- 

 work, what I have recounted for E. marshalll may be said to be 

 essentially applicable to the present species also. 



Marshall ('75) had described the occurrence of both the 

 circular and the longitudinal skeletal beams in sets of twos run- 

 ning side by side — such as might arise by the splitting lengthwise 

 of every, originally single beam — as somewhat constant and 

 characteristic of the species, which generalization has however 

 not been fully borne out by facts subsequently brought to light. 

 F. E. Schulze ('87, p. 79 ; '95, p. 30) has found in the small 

 specimen examined by him (Spec. C of the list on p. 205) that 



