EARLY PALEOZOIC BRYOZOA OP THE BALTIC PROVINCES. 203 



two or more exceedingly small tubed mesopores occupy the same 

 interzocecial space. This particular region affords a unique tan- 

 gential section showing quite large rounded zooecia and numerous 

 exceptionally small, angular mesopores. This condition is most 

 often presented at the surface of a zoarium and is a distinct aid in 

 the identification of the species. The tangential view, seen in figure 

 109 h, is the usual aspect of the species both at the surface and in 

 sections. 



The large zooecia and the very numerous small mesopores are alone 

 quite striking, but in combination with the oblique diaphragms and 

 lamellate method of growth afford characters unlike any other 



Fig. no.— Mesotetpa millepoeacea pakva. a, a zoarium, x2, showing the usual form; 6 and c, 



A TANGENTIAL SECTION, X20, WITH SEVERAL ZOCECU, X35; d, VERTICAL SECTION, X20, SHOWING ESSEN- 

 T^ALLT THE SAME STRUCTURE AS IN FIGURE 109 C. KUCKERS SHALE (02), BAEON TOLL'S ESTATE, 

 ESTHONIA. 



bryozoan save the following variety parva, which, as the name indi- 

 cates, is a smaller form. 



Occurrence. — ^The type-specimen was found by Dr. F. A. Bather 

 in the Chasmops limestone south of Bodahamn, island of Oeland. 

 An example incrusting the epithecated base of Diplotrypa petro- 

 politana, from the Jewe limestone (Dl), Baron Toll's estate (Cat. 

 No. 57285, U.S.N.M.), differs only in having shghtly smaller zocecia. 

 Other localities are Kuckers shale (C2), Baron Toll's estate (Cat. No. 

 57286, U.S.N.M.), and Kegel limestone (D2), Kegel, Esthonia (Cat. 

 No. 57287, U.S.N.M.). 



The type-specimen and figured thin sections are in the collections 

 of the British Museum. 



MESOTRYPA MILLEPORACEA PARVA, new variety. 



Text fig. 110. 



The internal structure of the specimens distinguished as above is 

 exactly the same as in the typical form of the species, and the differ- 

 ences rehed upon in founding the variety are the occurrence, first, of 

 a distinct method of growth and, second, of much smaller zocecia. 

 Ordinarily such differences, particularly the latter, would be con- 

 92602°— Bull. 77—11 15 



