96 GEOLOGY AND PALEONTOLOGY OF THE WEST INDIES. 



frontal is smooth, convex, surrounded by a line of large areolar pores often 

 separated by short costules. The apertura is suborbicular; the peristomice is 

 oval with a proximal pseudorimule. There are sometimes two quite incon- 

 stant, small, oral avicularia. The ovicell is endozocecial, enormous, borne 

 by a considerably enlarged zocecium; the frontal is garnished with radiating 

 and granulated costules. 



Measurements. Young zocecia: apertura, /ia = 0.14 mm., Za = 0.12 mm.; 

 zocecia: 1/2 = 0.60 mm., Zz = 0.28 to 0.30 mm.; old zocecia: apertura, /ia = 0.24 

 mm., Za = 0.16 mm.; zocecia: 1/2 = 0.70 mm., Zz = 0.24 to 0.30 mm. 



Affinities. The genus Metrarabdotos contains more species in 

 America than in Europe. The present species differs from Metrarab- 

 dotos moniliferum Milne-Edwards, 1836, common in the French 

 Miocene, in its granulated costules on the ovicell, in the absence of a 

 pseudo lyrule at the peristomice, and in the absence of oral avicularia. 



It differs from Metrarabdotos grandis of the Vicksburgian, which 

 also forms large fronds, in its greater zocecial width, and in much less 

 deep intercostular spaces of the ovicell. 



The species is quite variable and we have figured the principal 

 variations. 



Occurrence. Lower Miocene (Bowden horizon), Cercado de Mao 

 (Bluff 3), and Rio Cana (Zone H), Santo Domingo. 



Metrarabdotos lacrymosum, new species. 

 (Plate 3, Figures 1 to 10.) 



The following is a description of this species: 



The zoarium is free, bilamellar, bifurcated, narrow, with rectangular fronds, 

 and fastened by a little expanded base. The zocecia are distinct, little elongate, 

 rectangular, surrounded by large areolar pores more or less separated by the 

 costules. The apertura is oblique, semielliptical, divided in front by a rounded 

 and perforated sinus. The ovicelled zocecia are quite wide; the ovicell is 

 endozocecial; it is little salient, finely punctate, and ornamented with inter- 

 areolar costules. On each side of the apertura there are two large, triangular, 

 salient avicularia with their point directed above. 



Measurements. Apertura: ha = 0.18 mm., Za = 0.14 mm.; zocecium: 1/2 = 0.70 

 to 0.74 mm., 2 = 0.28 to 0.30 mm. 



Affinities. The characteristics of this species are the two large, oral 

 avicularia which hang from each side of the aperture like two large 

 tears. They are very irregular. 



This species differs from Metrarabdotos colligatum from the same 

 geological horizon in its little-expanded and non-prehensile base, in 

 its non-claviform fronds, and in the presence of large, oral avicularia. 



It differs from Metrarabdotos moniliferum Milne-Edwards, 1838, in 

 its much less costulated ovicell and in the absence of a spine in the oral 

 sinus. 



Occurrence. Lower Miocene (Bowden marl), Bowden, Jamaica 

 (common). 



