Vol. 52.] ANNIVERSARI ADDRESS OF THE PRESIDENT. XCV11 



having been met with in the Middle Coal Measuresof Cossall, near 

 Ilkeston, Derbyshire, by Mr. Edward Wilson, E.G.S., in 1876. 



It is highly probable that Diplostylus Daivsoni, Salter (1863), 

 from the Coal Measures of Nova Scotia, was related to Necroscilla 

 Wilsoni, but it does not appear to have possessed appendages to 

 the penultimate body-segment as seen in the latter genus. 



The remarkable genus Pygoceplialus, represented by P. Cooperi and 

 P. Ruccleyi, from the Coal Measures of Shropshire, Lanarkshire, etc. 

 offers characters common to the Stomatopoda, the Decapoda, and 

 the Schizopoda, showing clearly the narrowness and artificiality of 

 our classifications, which must ever need to be enlarged, in order 

 to embrace all the varied forms which now live or have existed in 

 past times. 



Small, but well-preserved, specimens of Crustacea, belonging to 

 the genus Squilla, described by Count Miinster, in 1839, as Sculda 

 pennata, are known from the Lithographic Stone of Solenhofen in 

 Bavaria. They differ little (save in the spinose ornamentation on 

 the abdominal and caudal segments and appendages) from the 

 existing species of Squilla. 



The Cretaceous deposits of Hakel, in the Lebanon, have yielded 

 to the patient labours of the late Rev. Professor E. B,. Lewis, 

 F.G.S., of the Syrian Protestant College, Beirut, a well-preserved 

 fossil Squilla which I described and named, in 1879, as S. Leivisii, 

 after that enthusiastic geologist. A Squilla from the same locality 

 (in 1886) has been named Sculda syriaca by Dames. Schliiter has 

 named two species, Pseudosculda Icevis and Squilla cretacea, from 

 the Chalk of Westphalia. 



Another fossil example met with was obtained from the London 

 Clay of Highgate by the late Mr. N. T. Wetherell, E.G.S., and was 

 described and figured by me, in 1879, as Squilla Wetlierelli. Lovisato 

 (1894) has recorded a Squilla miocenica from the Miocene of 

 Sardinia. These Secondary and Tertiary Squilla? all closely 

 approximate to existing forms of Stomatopoda, but the ancient 

 Carboniferous representatives of this sub-order suggest a more 

 generalized type of structure than those of later times. 



Notwithstanding their wide distribution in time and space, the 

 Squillidse are of rare occurrence — both recent and fossil. Two causes 

 may probably assist in explaining this : first, the thinness of the 

 test, which would render it less likely to be preserved ; and secondly, 

 the fact that all the species are fossorial in their habits, forming; 



