242 NEW YORK iSTATE MUSEUM 



Dalmanella penouili nov. 



Plate -13, figures 1-4 



This is a small circular shell without median depression or elevation 

 but with an elevated ventral valve and high cardinal area, simulating in this 

 regard an Orthothetes but without the deltidium and having a short hinge 

 line. The species is of the type of the Orthis lepidus Hall of the 

 Hamilton shale fauna but is of larger size than that little species is known 

 to attain. The surface of the valves is finely striate, the elevated radial 

 lines differing in size a few being considerably larger than the rest. 



Dimensions. The average among several examples is a width of 8 mm 

 and length of 7 mm. 



Locality. Portage road. 



Species name. Among the early French writers Gaspe Bay was the 

 Baie de Penouil. 



Hederella blainvillii sp. nov. 



Plate 48, figure 2 



This very interesting bryozoan encrusts the shells of Leptostrophia 

 blainvillii and so far as our observation has extended seems to attach 

 itself always to the ventral or upper valve at an early stage in the life of the 

 brachiopod and grow outward from the parent cell in all directions keeping 

 the apertures of the cells at or just a little distance above the margins of 

 the shell. This habit evinces a true commensal condition not often shown 

 in other cases of attached bryozoa ; the water currents set up by the ciliated 

 mantle of the brachiopod have helped to feed the members of the bryozoan 

 colony, most of which stand in an attitude of readiness for this service; 

 This species occurs with extraordinary frequency on these brachiopod shells 

 and seems to grow on no other save for an occasional simply branched stock 

 on an upper valve of Chonetes hudsonicus. Herein is another such 

 striking illustration of organic associations as we find exemplified in the 

 attachment of the coral Pleurodictyum problem at icum to Chon- 

 etes sarcinulatus and P. styloporato the gastropod Loxonema 

 h a m i 1 1 o n i a e. It is further exemplified in Hederella ramea which 

 I have described from the Oriskany of Becraft Mountain, N. Y. and which 

 elects attachment to Leptostrophia oriskani a, always keeping its 

 apertures toward the opening of the shell valves. From that species 

 H. blainvillii differs in its much more rapidly branching zoarium 

 and consequent shorter cells, producing a fuller and denser stock. 



Locality. Wherever Lept. blainvillii occurs in the Gaspe 

 sandstone. 



