DESCRIPTION OF ZANTHOPSIS CRETACEA 43 



Parahyba* They consist of some teeth and fragments of bones of a 

 fish, portions of the carapaces of two crabs, and one somewhat crushed 

 cephalopod. The cephalopod, Dr J. P. Smith f tells me, is a species of 

 Spheno discus, one of the so-called " Ceratites, 1 ' and of positive Cretaceous 

 age. 



MISS RATH BUN'S DESCRIPTION OF ZANTHOPSIS CRETACEA 



The crabs were submitted to Miss Mary J. Rathbun,of the Smithson- 

 ian Institution, and she has kindly furnished the following description : 



Zanthopsis, McCoy 



Zanthopsis, McCoy, Ann. Mag. Nat. Hist. (2), iv, 162, 1849. Zanthopsis cretacea, 

 Kathbun, sp. nov. 



Carapace about one and three-fourths times as wide as long. Surface densely 

 granulate, posterior portion punctate ; regions fairly well delimited. Six promi- 

 nent nodules: two median, one occupying the greater part of the mesogastric 

 region, one surmounting the cardiac region ; the other four are branchial, the 

 anterior pair in line with the gastric nodule, the posterior pair a little in front of 

 the cardiac nodule and a little outside the anterior pair; these last are high and 

 subcorneal; the posterior pair are lower and broader than long. Four less con- 

 spicuous nodules also exist — one on each protogastric lobe, one on each hepatic 

 area. A long, low protuberance lies behind each lobe of the front. The grooves 

 on either side of the narrow T mesogastric region are rather deep. 



The width between the outer angles of the orbits is a little less than one-third 

 the width of the carapace ; the front occupies nearly half the space ; it is produced 

 and divided by a median V-shaped notch into two lobes, with oblique margins, 

 forming a triangular tooth at the inner end, and a right angle at the orbital end. 

 The orbits are directed forward ; their margins show two fissures, separated by a 

 narrow, non-projecting lobe ; the outer angle is a little more advanced than the 

 outer angle of the front. 



The long antero-lateral margin bears at its middle two somewhat dentiform, 

 upturned lobes, defined on either side by deep grooves. Between these lobes and 

 the orbit, the antero-lateral margin is nearly straight ; behind the lobes, the mar- 

 gin forms the anterior border of a long, stout spine occupying the lateral angle of 

 the carapace. Postero-lateral margin concave. Posterior margin not distinguish- 

 able. 



The only appendages preserved are, in the larger specimen, a portion of the right 

 cheliped (carpus and palmar portion of propodus), and a fragment of the left dac- 



*Hartt mentions estherians found by Agassiz in certain green shales at Parahyba, from which 

 he, Hartt, infers that the beds are of fresh-water origin and equivalent to those of Bahia. C. F. 

 Hartt: " Geology and Physical Geography of Brazil," p. 445. 



These fossils, however, were never identified, and as estherians are not necessarily of fresh- 

 water origin, and inasmuch as the cephalopod shows that the deposits are marine, the correlation 

 must be regarded as unwarranted. Capanema says of a visit to Parahyba : "A badly preserved 

 crinoid leads me to suppose that the rock belongs to the Cretaceous," an equally hasty conclusion. 

 Trabalhos da Commissao Scientifica de Exploracfto, I, Seceao Geologica, p. exxii, Rio de Janeiro, 

 1862. 



t Professor of paleontology in Stanford University. 



