AFFINITIES OF THE GENUS SIPHONIA. 791 



decided as to the genus of a particular form, one is still not at all 

 sure as to whether it should rank as a distinct species or not. In 

 the face of these difficulties one must either restrict one's self to 

 mentioning those species only which have fallen under one's own 

 immediate attention ; or otherwise, in giving a complete history of 

 the group, with each of its described species, one must be prepared 

 to reserve judgment on a large number of forms, leaving their defi- 

 nite determination to future research and other observers. The 

 former is the less laborious of the two alternatives ; the latter, 

 however, is more thorough ; and though it leaves us in a state of 

 indecision on many points, it indicates on the other hand the lacuna 

 which remain to be filled up, and by supplying a reference to each 

 described species serves to save time in future inquiries. These 

 reasons appear to me sufficient to justify its adoption in the follow- 

 ing account. 



2. History. 



Descriptions of fossils more or less resembling SijpJionice occur in 

 the works of Langius, Scheuchzer, Bourguet, and various other 

 early writers on petrifactions ; but the first important paper on the 

 subject we owe to Guettard. 



1751. Guettard. ' Hist, et Mem. de l'Acad. Roy. des Sci.' (Paris), 

 torn. lxiv. p. 239. 

 In a paper entitled " Memoire sur quelques corps fossiles peu 

 connus " several specimens which are evidently Siplionice are de- 

 scribed and figured (plate i. figs. 1-4, plate ii. figs. 1-4, plate iii. 

 fig. 1) as possessing a more or less globular body, supported on an 

 elongated conical stalk below, and excavated at the summit to a 

 greater or less depth by a large circular cavity, into which smaller 

 radiating canals open. It is shown that these are not fossilized 

 fruits, as the common people of Normandy and Touraine imagined, 

 and as, indeed, some of the labourers in Devonshire believe even now; 

 and that they differ in important respects from the organism to which 

 Scheuchzer compared them — the Alcyonium Jlcus, Linnaeus, de- 

 scribed by Marsilli as " Eigue de substance d'Eponge et d'Alcion," 

 which Guettard considers, justly enough, to be a sponge, while the 

 " petrified pears " (our Siphonice) he assigns to the corals. 



1758. Baier. ' Oryctographia Norica' (Norimbergse), J. J. Baier, 

 p. 46, and Supplement, p. 59. 



In the body of this work the " fossil figs " (tab. i. figs. 30, 31) 

 are considered to belong to his division " Lusus Naturae-" but sub- 

 sequently in the Supplement they are referred to fossilized marine 

 vegetables resembling the Alcyonia (tab. vii. fig. 12). 



1769. Walch. 'Das Steinreich systematisch entworfen' (Halle), 

 J. E. J. Walch, p. 196, tab. xxiv. fig. 3 6. 

 Under the name " Corallinischen Eeigen " our fossils are here re- 

 ferred to a group of marine Fungites. 



3f2 



