^"{'89^''] PROCEEDINGS OF THE NATIONAL MUSEUM. 195 



wrinkled tiaiisvcrscly by con traction, ami also is rouglnMied by nu- 

 nicrons small elevations, whicii, however, do not represent t nix'iclcs or 

 verruca'. The spechnen is one ol" tln^ lew of the eolli'e(i(»n wlneh have 

 retained to a eertiiin extent tin'ir coloration, tlu', ectoderm of the 

 eolnnin wall being (»f adark biiek-red color. A noticeal)lc fcatnre is 

 the readiness with whicii tlu' thick ectoderm sei)arates from the meso- 

 ghea in large pieces; an explanation of this is found in the i)eculiar 

 struiitnre of the lower lay«'r of the eclo<leini. The ontei' layer of the 

 ectoderm contains a lew small nematocysts and a large nnmber of 

 gland c(^lls, some of whicii slain very deeply with cai'mine, while others 

 hardly stain atall. IJelow these there is a granular layer which stains 

 rather deeply, and next to the nu'soghea, occupying the region, where, 

 in the tentacles, for instance, the nerve layer is foun<l, is a broad, 

 slightly stained, tibrillar layer, in which arennmerons delicate spindle- 

 sha[)etl cells. It seems probable that this layer is more or l(%ss nervous 

 in its nature, but whether it is to be regarded as entirely nervous can 

 not be determined. It is in this layer that the ru|)ture takes i>lace, 

 when i)ortions of the ectoderm detach themselves, the structnnjof the 

 layer being delicate and nniceration of it easily brought about. 



The region of tlie column immediately above, (orijiternal to) the mar- 

 gin is much dei»ressed, appearing to re[)resent a distinct fosse, and at 

 the bottom of the depression there is present a strong circumsctjibed 

 endodernial sphincter (IM.xxxii, Fig. 104). In section itresembles closely 

 that whicii I have des(;ribed ('8t)) for Dincosoma anemone^ consisting of 

 a central axis from which processes arise, producing a more or less 

 pinnate a[)pearance. 



There being only a single specimen of the; form, 1 cut out only a 

 small portion of it for the examination of the s[)liincter, a]»iece of the 

 excised i)ortion being cut transversely for a study of the musiuilature 

 of the mesenteries. I can not accordingly give any facts as to the ten- 

 ta<',l(;s, disc, or st,omat()dieum, or even regarding the arrangement of 

 the mesenteries. A few tentacles were cnt in making sections of the 

 sphincter, and it was evident from these that their longitudinal 

 nuiscles were very weak. 



The small portion which wa« sectioned tor the purpose of ascertain- 

 ing the natiir«; of the musculature of the mesenteries contained repre- 

 sentatives of three cycles of mesenteries. Two of these l>ore lepro- 

 ductive (Ugans, while the third was sterile. Approximately the ex- 

 cised jiortion represented one-twelfth of the circumference, and it may 

 be coini)nted that there are at least twelve sterile (and i)erfect ?) pairs 

 of niescnteriesand twenty- four pairs that are go!ioi)hori(- (and imperfe(;t). 

 The mass of the mesenterial tihunents is very great, but no acontia 

 could be recognized. Theniusculature of themesenteriesis fairly strong, 

 gradually increasing in thickiu'ss from near the, i)arietal mh^a to about 

 the middle oftiie mesentery, where itabrnptly diminishes (PI. xxiii, Fig. 

 100); the parieto-basilars {phm) lorm distinct folds upon the surfaces 



