THE BRITISH FOSSIL BRACHIOPODA. 369 



inclines obliquely towards the principal lamella, the spirals being vertically arranged. 

 Mr. Glass, however, reminds me that the inclination of the secondary lamellae 

 occurs sometimes in Kayseria, but that he does not regard it as a permanent or 

 important feature, or as one upon which characteristic differences can be based. It is 

 just according to the way in which the two lamellae (primary and secondary) 

 happen to lie at their attachment to the dorsal valve, and it would be very peculiar if 

 they hung quite level to each other all through, or otherwise. This subject, however, 

 demands further investigations. 



Dr. Laube in his ' Die Fauna der Schichten von St.-Cassian,' 1S65, describes a new 

 genus, Amphiclina, and his figures lead Herr Zugmayer and myself to suppose 

 it to be a variation of Koninckina, but as no figure is given of its spirals, it is 

 not possible to speak decisively upon the subject. Koninckella is stated by M. 

 Munier-Chalmas to be possessed of spirals similar to those of Koninckina ; but he has not 

 yet, I regret to say, given any figure of them. Davidsonia is known to have been 

 provided with spirals, but the family or sub-family to which it should be referred has 

 not yet been satisfactorily determined. 



Since giving an account of Mr. Glass's and my own researches in connection with the 

 Spiriferida in the first and second portions of my ' Silurian Supplement,' I have received 

 from Dr. Waagen the second part of his work on the ' Carboniferous Brachiopoda ' of 

 the Salt Range, in which, while acknowledging the importance of the investigations 

 effected by Mr. Glass and myself, he gives the results of his own researches in connection 

 with this difficult and very interesting subject. 



Dr. Waagen was not, however, acquainted with the new arrangement of the genera 

 which Mr. Glass and myself proposed in the second part of my 'Silurian Supple- 

 ment,' and his operations have been limited to the very small number of spiral-bearing 

 genera that occur in the Carboniferous rocks of India; and these being much silicified 

 are very difficult to work, so that he has had, he says, to follow a somewhat different 

 process 1 to the one adopted by Mr. Glass. 



1 " The mode in which I operated was generally the following : The ventral or dorsal valve, 

 according to the side which I wished to expose, was carefully chipped off, then the matrix was smoothed 

 down cautiously, with a sculptor's rasp and occasional application of diluted acid, to near the spiral coils, and 

 then diluted acid was applied with a brush, aud an occasional touch of the rasp to remove the siliceous parts 

 until the spirals and their connections became visible. At the same time it was necessary to cover the parts 

 which were already sufficiently exposed, and had to be protected from the action of the acid, with sealing- 

 wax or Canada balsam. This mode of proceeding requires a great amount of time, as the specimen must 

 over and over again be dried and warmed for the application of the Canada balsam. With great patience 

 and care at last sufficiently clear preparations can be obtained in this manner to arrive at satisfactory 

 determination of these fossils. The sparry lamellae of the spiral cones and other parts come out then as 

 dark lines on the grey matrix. The process of cutting the matrix with a knife was not applicable on 

 account of the siliceous ingredients of the rock, making it of very unequal hardness at certain places, so 

 much so that it was only by dissolving the calcareous matter that the siliceous parts become sufficiently 

 disintegrated for removal " (pp. cit., p, 448). 



