394 TORREY 



The color of the column is dark red-brown ; the tentacles are much 

 lighter. 



Structure. — The body wall is thick, with a high columnar epithe- 

 lium which contains numerous gland cells, to whose pigmented con- 

 tents the color of the column is largely due. Nettle cells are also pres- 

 ent, but goblet cells are wanting. There is no suggestion of a mucous 

 covering. The mesogloea is thick — a sort of fibrous felt work w^ith 

 scattered nuclei. The endoderm possesses a layer of circular fibers, 

 strongly folded. Here and there a few fibers have been incorporated 

 into the mesoglcEa. The sphincter is strong, endodermal, subpin- 

 nate, circumscribed, with a moderate base (fig. 21). 



The longitudinal muscles of the tentacles are ectodermal. The 

 oesophagus has many folds. The ectoderm is thick, filled with gland 

 cells and nematocysts. There may be one or two siphonoglyphs. 



The mesenteries are arranged in five cycles. There are one or two 

 pairs of directives, according to the number of siphonoglyphs. 

 Twelve pairs are usually perfect above, those of the first cycle reach- 

 ing farther down on the oesophagus than those of the second, The 

 diglyphic forms may be regular or irregular ; for instance, the mesen- 

 terial formula in one specimen was D, 3, 3, 4, D, 6, 7, 8, 9, 10, 11, 

 12. One monoglyphic individual had thirteen pairs of perfect mes- 

 enteries. Both perfect and imperfect mesenteries are furnished with 

 mesenterial filaments, and all save those of the fifth cycle bear 

 gonads. Acontia are wanting. The parieto-basilar muscles are 

 strong, each in the form of a lobe similar to those in L. nympkcea. 

 The retractors are fiat, differing markedly from the extraordinary re- 

 tractors figured by Hertwig. 



E. ritteri may be distinguished from E. prolifera by its larger 

 size, the shape of the sphincter, and the absence of the habit of carry- 

 ing the young externally. 



Family SAGARTIID-ffi Gosse. 



ActiniiuEe with adherent pedal disk ; with a mesogloeal, rarely a 

 weak endodermal, sphincter; with acontia, which are either emitted 

 through the mouth alone or also through special openings (cinclides) 

 in the column wall. (McMurrich, 1901, bS) 



Snhi^mWy ME TR ID IIN^^ Carlgren. 

 Segartiidas with six or more pairs of perfect mesenteries ; body wall 

 wall relatively thin, and without a cuticle : cinclides present ; usually 

 well-developed mesogloeal muscle. 



