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Cincinnati Society of Natural History. 



and so far from their being the remains of plants, they are the reproduc- 

 tive bodies of Hydrozoa. According to Nicholson (Monograph of Brit- 

 ish Graptolitidae, Part I., p. 70), the first information respecting these 

 bodies was given by Professor Hall in 1848, when he described what he 

 took to be "reproductive bodies" or " ovarian capsules" of Diplograptus 

 Wliitfieldii. In 1866, Dr. Nicholson announced the discovery of these 

 "ovarian capsules" in the shales of Dumfriesshire, England. These are 

 described (Ibid, p. 72), "when compresses laterally, as oval or bell-shaped 

 bodies, provided at one extremity with a prominent spine or mucro ; and 

 the larger examples may be as much as from three-tenths to four-tenths of 

 an inch in length, and from one-tenth to two-tenths of an inch in breadth." 

 They exhibit little or no definite structure. When compressed from above, 

 "they appear as rounded or oval patches, often very definite in their out- 

 lines, and exhibiting somewhere within their margin an elevated point, 

 surrounded by several concentric, elliptical or circular rings, disposed with 

 more or less regularity." The specimens of Lockeia siliquaria present 

 no concentric or other lines. They are scattered promiscuously over the 

 surface of the shaly rock, are from one-eighth to one-fourth of an inch 

 long, and are from two to four lines wide at the base. Sometimes the ends 

 are prolonged into points, sometimes they are obtuse; sometimes a longi- 

 tudinal ridge runs along the top, and sometimes there is a slight depression 

 in the center. They lie slightly attached to the rock, and can be easily 

 separated from it. They show no signs of organic structure, and it is 

 likely that this was all destroyed during the process of fossilization. 

 Though unable to assert to what species of Hydrozoa these bodies be- 

 longed, it seems probable that they are really fossilized "ovarian capsules" 

 of some of those species which are found so abundantly in the rocks of 

 this group. It has been objected to this, that there have been found no 

 Graptolites in the horizon where the Lockeia is abundant; but if the 

 varieties of Buthotrephis are really Graptolites, as I believe them to be, 

 then surely in these species the polyparys or stipes are large enough to 

 bear bodies of the size of the Lockeia. 



Impressions of Organisms. 



While many of the "fucoids" have been described from fossil mud-marks, 

 many from annelid burrows and gasteropod trails, a few from Graptolitic 

 remains, still others have their origin in impressions left by organisms on 

 the mud. These come under examination now, and an attempt will be 

 made to clear up the obscurity resting on the nature of some of these 

 forms. 



