ANNIVERSARY ADDRESS OF THE PRESIDENT. XCVU 



Echinodermata, which are divided into eight orders. But of these 

 the Sipunculoidea and Ilolotlmroidea are not found in a fossil 

 state ; and the Blastoidea and Cijstoidea are peculiar to the 

 Palaeozoic rocks ; consequently v^^e have here only to consider the 

 remaining four orders, the JEcldnoidea, Asteroidea, Ophiuroidea, 

 and Crinoidea. Dr. Wright then gives a descriptive analysis of 

 the component elements of the test and body of the Echinoidea, 

 which consists of three parts : 1st, the test or calcareous envelope, 

 of various forms, and composed of a framework of plates, which are 

 either hexagonal, pentagonal, or polygonal ; 2nd, the visceral 

 cavity, containing the different organs ; and 3rd, the external 

 spines and tubercles. They are divided into two sections, E. en- 

 docycUca and .£/. exocyclica, which are subdivided into thirteen 

 natural families, of which the Cidaridce are the first, and to which 

 this first part of the work alone applies. Some idea may thus be 

 formed of the magnitude of the work undertaken by Dr. Wright. 

 Thirteen species ai'e here described, illustrated by eleven plates, 

 of which it is not too much to say that they ax-e probably the 

 most perfectly executed plates published by this or any Society. 



The next paper is the commencement of Mr. Salter's Mono- 

 graph of British Trilobites, with six plates. He commences with 

 a short account of the history or literature of Trilobites and the 

 progress of their discovery, with special allusion to the works of 

 Burmeister, Quenstedt, Emmerich, Barrande, and others, fol- 

 lowed by a sketch of their vertical range, structure, and habits, 

 with a provisional classification, in which the Phacopidcs are placed 

 as the typical and most perfect group of the order. Eorty species 

 are here described and figured, chiefly belonging to the Fhacopidce 

 and CheiruridcB. 



The third paper is by Mr. Davidson, on the British Devonian 

 Brachiopoda. It is the first portion of the 6th part of his great 

 work on British Fossil Brachiopoda. I have already to-day alluded 

 to the great claims on your approbation which Mr. Davidson has 

 acquired by the manner in which, for the last thirteen years, he 

 has laboured with unvarying zeal and diligence at this important 

 work. I shall therefore now only briefly allude to the contents 

 of this portion. In the preliminary remarks, Mr. Davidson refers 

 to the remarkable break which exists in Devonshire between the 

 Devonian and Silurian rocks, and possibly in other regions, 

 and quotes Professor Eamsay as stating that of several hundred 

 Upper Silurian forms, only about six occur in the Lower Devonian 

 rocks. He then refers to the observations of Mr. Pengelly, Pro- 

 fessor de Koninck, Bamsay, Salter, and others. In Morris's ' Cata- 

 logue of British Eossils ' ninety-four species of British Devonian 

 Brachiopods have been enumerated ; many of these Mr. Davidson 

 considers as only synonyms ; but there is great difiiculty in iden- 

 tifying some of these so-called species, partly from the want of 

 sulficiently perfect material, and at times also from insufiiciency 

 of description and illustration. For the present Mr. Davidson 

 reserves what he may have to say witli reference to those spe- 



YOL. XXI, g 



