H. WOODWARD OX NEW KIMMERIDGE-CLAY HACRTTRA. 49 



warded to me for examination by Mr. Henry Willett, F.G.S., had 

 not my friend, Mr. John E. H. Peyton, F.G.S., of St. Leonards (who 

 has devoted much attention to the question of the true geological 

 horizon of the Sub-Wealden boring) gone over to Boulogne-sur-mer 

 in September 1873, to examine the Kimmeridge Clay of that locality, 

 where he not only obtained several specimens of Lingida ovalis, Sow. 

 (new to that locality), but also a small but nearly perfect example of 

 a Crustacean referable to the genus Mecochirus. 



This genus (like Callianassa) early attracted the notice of geo- 

 logical writers. It was first described as a " Locust " by Knorr in 

 1755, then as an Astacus by Bajer in 1757, as a Macrourites by 

 Schlotheim in 1820, and as a Palcemon by Kriiger in 1823 <fe 1825. 

 It was not, however, correctly defined and separated from other genera 

 until 1827 (by Germar, in Keferstein's Deutschl. Bd. iv. p. 102), since 

 when it has been repeatedly noticed and the species figured by Holl, 

 Bronn, Miinster, Mayer, Pearce, Quenstedt, M'Coy, Pictet, Oppel, 

 and others. 



The oldest species is the Meeocliirus olifex, Quenstedt, from the 

 Lower Lias of Dusslingen, near Tubingen, Wiirttemberg*. 



Next in ascending order is the Mecochirus (Cancrinium) socialis, 

 of Meyer (1841) from the Kelloway group, Wiirttemberg and Nor- 

 mandy. 



To this species {Mecochirus socialis, Meyer, sp.) Dr. Albert Oppel 

 has referred the Mecochirus (Ammonicolax) Pearcei, from the Oxford 

 Clay of Christian Malford, near Chippenham, Wilts, which he con- 

 siders a part of the Kelloway group. 



I have not had the good fortune to see a specimen of Meyer's M. 

 socialis ; but, comparing his figures of that species with specimens of 

 M. Pearcei in the British Museum (from the collection of Mr. 

 William Cunnington, F.G.S.), and with other specimens obtained di- 

 rect from Mr. William Buy (late of Sutton near Chippenham), I 

 am satisfied the specimens from Wiltshire should still be retained as 

 belonging to a distinct species as established by M'Coy in 1849 

 (Ann. & Mag. Nat. Hist, series 2, vol. iv. p. 172). 



The remaining four species of Mecochirus, namely M. longimanus, 

 Schloth., M. Bajeri, Germ., M. brevimanus, Miinst., and M. dubius, 

 Miinst., are from the lithographic stone of Solenhofen, Bavaria. 



Like other species of this remarkable genus, the fore limbs of 

 Mecochirus Peytoni are equal to the length of the entire body. They 

 measure 75 millims. in length, of which the terminal joint (dactylus) 

 measures 18, the propodos 30, the carpus 5, the meros 18, and the 

 ischium and basos 4 millims. The surface of the fore legs is very 

 finely punctate. 



The carapace, which is finely granulated, measures 30 millims 

 from the rostrum to the posterior border, and 14 millims. in depth 

 from the mesial dorsal line to the lower margin of the branchial 

 region. The rostrum is somewhat produced. 



The antennae are not well preserved, but are long and slender. 



* Wiirttemb. naturw. Jahresh. 1850, Bd. vi. p. 186 ; Quenstedt, der Jura, 

 1856, p. 89, tab. 2. fig. 17. 



Q. J. G. S. No. 125. b 



