WIDERSTEN: ANTHOZOA FROM EASTERN COAST OF UNITED STATES 



sandy bottom, on a tube fragment of an onuphid 

 polychaete. 



DIAGNOSIS.-Column rather firm, smooth, 15 

 mm tall, bright red (sometimes whitish) to reddish 

 brown in color. Tentacles rather short, with well- 

 limited acrospheres; two or three per endocoele, 

 the .total number being 90. Sphincter long, ento- 

 dermal to ento-mesogloeal. Maximum number of 

 mesenteries 60. At least six pairs of mesenteries 

 perfect. Retractors diffuse. Cnidom: column — 

 holotrichs and spirocysts; tentacles (acrospheres)- 

 holotrichs and microbasic b- and jo-mastigophors; 

 tentacles (peduncles)- microbasic h- and jo-masti- 

 gophors, atrichs (?), and spirocysts; actinopharynx- 

 holotrichs, atrichs, microbasic p-mastigophors, and 

 spirocysts; ^A7a me/? ^s— holotrichs, microbasic p- 

 mastigophors, atrichs (?), and spirocysts. 



GENERAL CHARACTERISTICS.-The col- 

 umn is smooth and rather firm. In the contracted 

 state there are distally a number of transverse 

 as well as a few longitudinal furrows. The shape of 

 the column is proximally dependent on the shape 

 of the substrate. The color of the column and the 

 pedal disc is bright red to reddish brown. (There 

 are also, however, some whitish individuals in the 

 collection, with red mesenterial insertions shim- 

 mering through the ectoderm.) The longitudinal 

 muscle sheet of the ectoderm forms a thin, but 

 distinct layer in the column. The tentacles are 

 rather short, with cylindrical peduncles and well- 

 limited, white acrospheres. The entodermal as well 

 as the ectodermal muscle sheets of the peduncles 

 are well developed. The inner tentacles are shorter 

 than the outer ones; the exocoelic tentacles are the 

 largest. The stichodactyline arrangement of the 

 tentacles is rather indistinct in the often strongly 

 contracted specimens of the collection. There are, 

 however, two or three tentacles per endocoele, the 

 total number being 90. The sphincter is long, 

 entodermal to entomesogloeal (Figure lA), and 

 is only occasionally capable of covering all the 

 tentacles. The actinopharynx is short, in the 

 contracted state, with longitudinal as well as 

 transverse folds. There is only one indistinct 

 siphonoglyph. The retractors of the maximum 60 

 mesenteries are diffuse, forming an insignificant 

 sheet over the edge of the mesentery (Figure IB). 

 At least six pairs (including the directive pair) of 

 the mesenteries are perfect. Reproduction is 

 probably asexual by longitudinal fission. The size 



B 



Figure l.-Corynactis delawarei n. sp. A. Section through the 

 sphincter region of the column. B. Cross section of a perfect 

 mesentery, ent-entoderm, mgl— mesogloea. 



of the normally cylindrical column is of a max- 

 imum 15 mm, with a proximal diameter of 8 mm. 



NEMATOCYSTS.-Column: holotrichs 38 x 8.7 

 - 53.4 X 10.9; spirocysts 18.5 x 3.3 - 27 x 4.4. 

 Tentacles (acrospheres): holotrichs 69 x 21.8 - 85 

 X 10.9-16.4; hoplotelous microbasic p- 

 mastigophors 33 x 5.5 - 82 x 8.8-9.7; hoplotelous 



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