396 Mr. J. Blackwall on the Sb'ucture, Functions, (Economy, 



cord-like ridge formed by the casts in them on the under surface 

 of the laminae, might possibly be mistaken for a different worm 

 resembling a Gordius, without due caution or the absolute de- 

 monstration of their nature, afforded by many of the speeimensi; 



Very abundant in the greenish slate of Thomey Lee quarryy 

 on the Tweed, near Inverleithen. . Tt 



{Col. University of Cambridge.) 



Tr achy derma "i Icevis (M'Coy). 



Sp. Char. Tube slightly curved, thin, coriaceous, slightly taper- 

 ing, subcompressed ; slightly more than 1 line in diameter at 

 the broad end, and slightly less than 1 line at the imperfect 

 smaller end of a specimen 1 inch 7 lines long ; surface nearly 

 smooth. 



The specimen is a brown, tough, flexible tube, irregularly and 

 gently compressed (parallel to the plare of stratification of the 

 rock), assuming an oval section ; and being filled with the bright- 

 coloured matrix shows clearly the thinness of the tube, which, 

 from the same cause, has a few irregular indentations of the sur- 

 face, which otherwise seems smooth. 



E-are in the fine beds of Caradoc sandstone of Acton Scott, 

 Church Stretton. 



{Col. University of Cambridge.) \ 



XL. — A Catalogue of British Spiders, including remarks on their 

 Structure, Functiuns, (Economy, and Systematic Arrangement. 

 By John Blackwall, F.L.S. 



[Continued from p. 262.] 



13. Lq/cosa cambrica. 

 Lycosa cambrica, Blackw. Linn. Trans, vol. xvili. p. 614. 



Adult males and females of this handsome s])ider were taken on 

 swampy ground in woods at Oakland, near Llanrwst, in May 

 1839. The decidedly curved form of the maxilla;, an approxi- 

 mation to which may be observed in Lycosa campestris, Lycosa 

 allodroma, and some other species, has not been considered of 

 sufficient importance to require its separation from the genus 

 Lycosa, with the scmiaquatic species of which genus it is very 

 closely allied by its general organization, habits and colours. 



I have observed a deficiency of the right intermediate eye of 

 the anterior row in an adult niale of this spider. 



M. Walckenaer is certainly mistaken in siip))o.sing that Lycosa 

 cambrica is identical with Lycosa allodroitm (jlj&tr; Nat. dcs In- 



