52 Papers from the Marine Biological Laboratory at Tortugas. 



self has defined his genus in a somewhat tentative way, and admits the 

 lack of conformity as to the sphincter character, I am disposed to refer 

 the species provisionally to the genus Cradactis, no representative of which 

 I have seen, till such time as further facts may call for other adjustment. 



So far as I have been able to ascertain, the species has not been 

 hitherto described. I propose for it the specific name variabilis, as indic- 

 ative of the extremely variable features exhibited. The following may 

 be regarded as fairly diagnostic, so far as one may make up a definitive 

 account from poorly preserved material. It may be said, however, that 

 I have had the advantage of such verbal account as Dr. McClendon was 

 able to give from memory. 



Column low, in preserved specimens (McClendon gives it as his 

 impression that in expansion it is about twice the diameter), smooth, 

 with broader base than oral disk, the latter concave, with raised mouth 

 which is oval in shape and as usual diglyphic. Tentacles somewhat 

 finger-like, but in extension tapering to a delicate tip, about 30 to 40 in 

 number or more in the largest specimens. The most remarkable feature 

 is the peculiar frond-like organs situated about the margin of the oral 

 disk and just outside the outer cycle of tentacles. There are usually 

 6 of these organs, more or less symmetrically arranged, though the 

 number varies considerably, being frequently but 5 and sometimes as 

 many as 7. Typically these are dichotomously forked once or occasionally 

 twice, and the tips usually knobbed, as shown in some of the figures in 

 the plate. Upon the upper surface of these organs there is usually a 

 whitish disk or pad, sometimes several. These are shown in section to 

 be glandular organs, and possibly secrete a substance, probably of an 

 adhesive nature, such as might aid the creature in capturing prey. 

 They are also provided with several large nematocysts, and the produc- 

 tion and discharge of these may be an important, perhaps the most 

 important, function they serve. 



The specimens seem to have the capacity to move about more or 

 less freely, and it seemed to me these organs might aid in such movement ; 

 but McClendon is of the opinion that the tentacles are used for this 

 purpose. It will be observed that several of the figures of the plate show 

 specimens inverted, that is, adhering to the bottom of the aquarium by 

 the oral end, the pedal disk being uppermost at the time the photograph 

 was made. It may be stated that the photograph was taken of a series 

 of specimens just as they happened to be disposed in the dish, and shows 

 in a very striking way the remarkably variable character of the creatures. 



Color pale olivaceous-green to brownish; tentacles somewhat lighter; 

 foliose organs darker, even brownish, with flake -white pads, sometimes 

 with a darker center, and with whitish lines extending along the upper 

 side, especially in the region of the pads and towards the tips. 



The body seems to be rather highly contractile, but there is only a 

 weak or diffused sphincter, and none of the specimens showed any con- 

 siderable contraction of the oral disk, or the retraction of the tentacles. 

 The mesenteries are numerous, apparently hexamerously arranged. 



