192 Dr. M. Laurie on the 



We have thus three types of structure for the lamella, 

 which we may term the spinous, arcade, and reticulate forms. 



The spinous type occurs in Scorpio, Ileterometrus, Opisth- 

 ophthahnus, Palamnceus, Opisihocentrus, Hormurus, and 

 Urodacus among the Scorpionidge ; in tScorpiops, Vejovis, 

 Iladrurus, and Broteochactas among the Iuridse ; and in the 

 only member of the Bothriuridas which I have seen, namely 

 Botliriurus. From its wide range this type of lamella is 

 probably the most primitive. 



The arcade type occurs in Diplocentrus and Nebo among 

 the ScorpionicUe, and in Iurus, Caraboctonus, and Euscorpius 

 among the Iuridse. 



The reticulate type occurs in Buihus, Parabuthus, Uro- 

 plectes, and Centrums, all belonging to the Buthidse. 



The morphological value of the lamellas is probably less 

 than that of the development. 



The following table summarizes the two sets of facts and 

 gives a list of the species I have examined : — 



Development. Lung-books. 



Scorpio fulvipes (C. Koch) Scorpio type. Spinous. 



Ileterometrus, sp „ „ „ 



Opisthophthalmus capensis (Herbst) .... „ „ „ 



Balamnaus Thorellii (Poc.) „ „ „ 



Opisihocentrus madagascariensis (Kraep.) „ „ „ 



Opistliocentrus validus (Thor.) ? „ 



Hormurus australasice (Fabr.) Scorpio type. „ 



Urodacus novte-hollundice (Pet.) ? „ 



Scorpiops Hardiuickii (Gerv.) ? „ 



Vejovis, sp. ined Euscorpius type. „ 



Iladrurus hirsutus (Wood) „ „ „ 



Broteochactas delicatus (Karscb) „ „ „ 



Bothriurus bonariensis (Kock) „ „ „ 



Diplocentrus Whitei (Gerv.) ? Arcade. 



Neboflavipes (Sim.) ? „ 



Iurus JJufoureius (Brulle) ? „ 



Caraboctonus Keyserlingii (Poc.) ? „ 



Euscorpius italicus (Herbst) Euscorpius type. „ 



Buthus nigrolineatus (Dufour) „ „ Reticulate. 



Parabuthus capensis (Gerv.) „ „ „ 



Uroplectes trianyulifer (Thor.) ........ ,, „ , f 



Centrums gracilis (Latr.) „ „ , 



The number of forms examined is far too small to base 

 deductions on with any certainty, and to classify on the 

 ground of these two structures alone would be almost certain 

 to lead to a wrong conclusion, 

 to suggest the following rearrangement : 





The results seem, however, 



