368 Mr. R. I. Pocock on the History of a 



Sloanei. This description is also repeated and amplified in 

 the Linnean ' Transactions ' and in the ' Catalogue.' In the 

 Linnean ' Transactions ' Newport refers to the resemblance 

 between these two species and points out the characters by 

 which thej may be separated. Curiously enough, however, 

 he nowhere gives the number of antennal segments of piU- 

 cornisj whereas he asserts that Sloanei possesses forty. And 

 since, in his comparison of the two species, there is no state- 

 ment that any structural difference is found in these appen- 

 dages, the obvious inference is that pilicornis also possesses 

 forty segments. Add to this that pilicornis is said to be 

 English, while there is no locality for Sloanei, and we have 

 sufficient information, one would think, to lead to the identi- 

 fication of at least pilicornis. No mention, however, of either 

 has been made for more than thirty years, and but for what 

 may be termed a lucky chance both might for many a year 

 have still remained amongst the category of long-forgotten 

 species. 



During a trip to Cornwall in the autumn of 1890 my friend 

 Mr. Oldfield Thomas was fortunate enough to capture upon 

 St. Michael's Mount a magnificent specimen of the genus 

 Lithohius. 



It is manifest at a glance that this specimen is markedly 

 diflferent from the common British members of the family ; 

 for it far exceeds in size the largest examples of L. forficatns 

 and L. variegatus, the two species which have hitherto shared 

 the distinction of being generally considered the giants of the 

 race — so far at least as Britain is concerned. Moreover, a 

 closer inspection shows that, apart from its size, this new 

 comer may be distinguished by sundry well-marked structural 

 features from all its near relatives that are commonly met 

 with in England. From a systematic point of view, in 

 fact, its specific characters are at least as important as those 

 which distinguish forficatus from variegatus or crassipes from 

 microps. 



Taking this into account, and not at the time recollecting 

 that any similar or even remotely allied species had been 

 described on the continent from the countries of which the 

 Myiiopod fauna is known, I had reasonable grounds for 

 expecting that this one would prove to be new to science, and 

 that we should have the satisfaction of recording a second 

 species of the genus as peculiar to the British Isles. Refer- 

 ence, however, to literature, accompanied by a careful reexam- 

 ination of the specimens of this genu.< that arc contained in 



