Fauna, Subterranea. 147 



Thysanoura, — white, of considerable size, and approaching to the 

 genus Anurophorus, Nicolet, on account of its want of a scaly co- 

 vering, its rudimentary apparatus for jumping, the structure of 

 its antennae and limbs, as well as the number and position of its 

 eyes. The antennae are strikingly different from those of the 

 well-known species, being longer than the head ; the legs, besides, 

 are longer and more slender ; and the structure of the pectoral 

 segments is remarkable, each being subdivided by a stricture 

 into two unequal parts. It is exceedingly difficult to discover the 

 eyes, and it was only after many attempts that I ascertained their 

 existence, form, number and position, by the aid of Lieberkiihn's 

 mirror and a powerfully reflected lamp-light. They are snow- 

 white, fourteen on each side, and placed nearly as in Anurophorus 

 Jtmetarius.* Their colour plainly indicates their being rudimen- 

 tary, and unfit for sensation. 



Smaller specimens, found together with the larger ones, differed, 

 besides their size, by the short antennae having a large terminal 

 joint, and the pectoral joints being less strongly constricted ; I con- 

 sider them to be a younger age. Conjointly with these two forms 

 I met with a third, much smaller, linear, with very short antennae, 

 very feeble traces of constriction in the pectoral rings, and the 

 abdomen furnished at the end with two small hooks. This small 

 form, I think, is the larva state. 



Anurophorus Stillicidii. 



Niveus, oculis viginti-octo ; antennis capite duplo longioribus; 



segmentis thoracicis bilobis. 

 Long. 1| lin. 



Many of the stalactites have lateral projections, arising from 

 the inequality of the droppings from which they have originated. 

 From these projections water drops down, which strikes on those 

 below ; and this is particularly the case, where the stalactites 

 have reached the roof of the vault. Carbonate of lime is in time 

 deposited between the adjoining projections, which thus gra- 

 dually approach each other, beginning from without, so that a 

 small recess is often formed between two projections, preserving 

 its outlet, until their whole breadth is united. These little cavities 

 are inhabited, in the Magdalena and Adelsberg caves, by two 

 remarkable blind Arachnidans, each the type of a new genus. 



* Nicolet, Recherches pour servir a l'Histoire des Podurelles, pi. 2, fig. 19. 



L 2 



