I90I S. S. BUCKMAN — BRACHIOPODA 245 



The multiplicate stage of development is uncommon 

 among the Terebratulidai ; but among the RhynchoneUidae 

 it is dominant. With the great majority of them it begins 

 with the growth of the test, showing that it has been a 

 long inherited character. With others, however, it does 

 not begin till some growth has been completed. Mr 

 Upton shows one such form, which he calls Rhynch. 

 cottesivoldicr : therein the multiplicate character is just 

 beginning to assert itself. Such a character, judging by 

 the young of the species, must be a development inde- 

 pendent from the settled multiplicate character of Rhynch. 

 tetraedra, or from the curious developments of plicae in 

 the Rh.-acnta group. So it may be assumed that Rh. 

 cottestvoldice is developing plications as a new feature of 

 its own, not as the result of inheritance ; and that the 

 multiplicate character in the Rhynchonellidse is polygenetic. 



I take the opportunity to figure an interesting new 

 species, which shows plicae of a more settled character 

 than Rh. cottesivoldics, and yet that they do not begin till 

 the shell is well grown — so that in this case the character 

 appears to be new. Further in this species the brachial 

 valve is sulcate, and that is a character which most Rhyn- 

 chonellcs have grown out of, though it is the dominant 

 character in genera of Terebratulidae and Magellaniidae ; 

 viz., Psetidoglossothyris, Glossothyris, Aulacothyris. 



3. RHYNCHONELLA STANDISHENSIS, 5. Buckman, sp. nov. 



PI. XII., figs. 13-15. 



Description. — A small, sub-circular, depressed Rhynchonelloid, with 

 a carinate pedicle valve, a sub-sulcate brachial valve, the sulcus ex- 

 tending nearly to the umbo; in each valve about 16 plaits extending 

 only half-way from the margin, no definite mesial fold, but the three 

 central plaits slightly larger than their fellows. 



Distinction : — From Rhynchonella Meneghinii, Zittel, 

 the general form of the shell is rounder, the plicae are 



