372 GENER/VL SUMMARY TO 



encloses the visceral canal in some species of Athyris, and which terminates at the apex 

 of the valve in the visceral foramen. . . . The crura, as has been said above, take 

 their origin on both sides of the cardinal process at the margin 

 of the dental sockets. They are slender, not very long, rather 

 straight, and extend in an obliquely ascending direction. They 

 join the primary descending lamellae of the spirals with a very 

 acute bend. The primary lamellae are very strange in their 

 development. They show broad wing-like expansions at their 

 origin, which are sometimes very strongly developed, as in the 

 specimen figured in the woodcut, sometimes less so, but they 

 are always present. Very near below the origin, from the broad 

 part of the primary lamellae, the loop proceeds. It consists of 

 two slender, nearly quite straight lamellae, which converge about 



Eumetria qrandieosta, Dav. • .1 , - ,. n ., , . » ,1 -, 1 ,1 



sp. (after Waagon). in the direction oi the longer axis or the valve towards the 

 primtrfia V m e e V iiK £theloopand middle > and unite in forming a little sharply-pointed spur, which 

 is directed obliquely towards the apical part of the valve. From 

 the origin of the loop the primary lamellae taper very quickly. 



" The spirals are very loosely coiled, and consist of six to eight volutions. Whilst the 

 primary lamellae on the dorsal side approach each other very nearly, their recurving 

 branches on the ventral side are rather distant from each other, so that the entire loop 

 lies open to inspection. . . . From this description it appears that the shells which 

 I subsume under the name of Eumetria can be very well distinguished generically from 

 other genera of the sub-family. The most striking features are the wing-like expansions 

 of the primary lamellae, the origin of the loop so near the commencement of the 

 primary lamellae, and its extension forward in a horizontal direction, just the opposite of 

 what takes place in the genus Hindella. The genus Eumetria thus seems to be much 

 more removed from the remainder of the genera of the Retziince than the genera 

 Nucleospira, Refzia, and Meristina are from each other." 



Dr. Waagen states likewise that a somewhat more circumstantial description of 

 the internal parts will be found in Derby's paper on the Brachiopoda of the Itaituba 

 Province of Parti, Brazil, 1 a paper which is full of much valuable information about the 

 interior structure of these Molluscoids. 



I have given these lengthened extracts from Dr. Waagen's work because it is 

 probable that one or two of our British species, when better known, may perhaps have 

 to be referred to the genus Eumetria. 



In his sub-family Uncitina (p. 494) Dr. Waagen proposes a new genus Uncinetta, 

 type U. indica, Waagen, but says that its internal characters could only be partly 

 made out. 



1 ' Bulletin of the Cornell University of Science,' vol. i, No. 2, p. 4, 1874. 



