62 PEOCEEDINGS OF THE IsTATIOlSrAL MUSEUM 



Table 16. — Record of specimens of Euplectella oweni 



VOL. 81 



Specimen A is the smallest one in the collection. It measures 113 

 mm in length, excluding sieve plate/ and the broadest part - (ledges 

 included) is 24 mm in diameter. The compressed lower end of body 

 measures 13 mm in diameter, and the part immediately below the 

 sieve plate is about 8.5 mm in diameter. This specimen is rather 

 delicate in form, with thin walls and inconspicuous parietal ledges, 

 which frequently form irregular ribbonlike masses or protuberances. 

 It somewhat differs from typical E. oweni in the presence of a 

 lophocome, in the number of transverse and longitudinal beams 

 relative to the size of entire stock, and in having weakly developed 

 parietal ledges. Nevertheless, I think it advisable to identify this 

 form with the present species. 



First, the lophocome (though somewhat different from that of 

 E. Tnarshalli in its dimensions) scarcely deserves to be considered a 

 character of such systematic significance as to warrant establishing 

 a new name. The lophocome may possibly exist in E. oweni, even 

 though it has not yet been described in the hitherto known specimens. 



Secondly, the proportional number of transverse and longitudinal 

 beams is not a constant character in these sponges, especially in 

 young specimens, thus also losing its importance as a distinctive 

 specific character. The numbers of transverse and longitudinal 

 beams in this specimen are as follows : Circular beams, 52 ; longitudi- 

 nal beams at upper end, 25; longitudinal beams at middle, 34; 

 longitudinal beams at lower end, 19. 



The above-mentioned characters seem to indicate some relationship 

 with E. inaTshalli. The lophocome occurs quite rarely and singly. 

 The diameter is 61;ii. The principal rays are 4/t to 6/i in length. 

 The terminals are 22/x. to 24/* long and exceedingly fine. They are 

 pointed at the outer end and arise close together from all parts 

 of the outer disk surface. The peripherally situated terminals in 

 each tuft are slightly but distinctly flaring, so that the tuft may 

 be said to be campanulate. 



iThe sieve plate is damaged and therefore is excluded in measuring the total length of 

 the body. 



2 Breadth measured after restoring compressed body wall to a cylindrical form. 



