PLATE X. 



Fig. Page. 



Illaenus portlocki, Salter? 67. 



1. Head-shield, perhaps referable to this species, x lj. Craighead. Mrs. Gray's Collection. 

 la. Side view of same specimen, x 1£. 



Illaenus shallochensis, sp. nov. 68. 



2. Complete individual, viewed froni above. x 1^. Thraive Glen. Mr. Macconochie's 



Collection. (The pygidium is foreshortened as the specimen is partially enrolled.) 

 2a. Side view of same specimen, x 1|. 

 2b. Pygidium of same specimen, x 1 | . 

 2c. Inferior surface of head-shield of same specimen showing epistome, etc. x 1J. 



3. Pygidium, showing ornamentation of shell. x l.\. Shalloch Mill. • Mrs. Gray's 



Collection. 



4. Pygidium of young individual. ? X 3. Same locality and Collection. 



5. Epistome. x 1 -£. Same locality and Collection. 



Illaenus thomsoni, Salter. 70. 



6. Free cheek, viewed from below, showing doublure. Nat. size. Rough Neuk, Mulloch Hill. 



Mrs. Gray's Collection. 



7. Free cheek, viewed from above. Nat. size. Same locality and Collection. 



8. Epistome. Nat. size. Penkill. Same Collection. 



Illaenus. Cf. oculosus, Holm. 71. 



9. Head-shield, showing right eye. x 2\. Ardmillan. Mrs. Gray's Collection. 



10. Free cheek, x 11. Same locality and Collection. 



11. Head-shield, x lh. Same locality and Collection. 



Illaenus. Cf. perovalis, Murchison. 72. 



12. Pygidium (axis abraded), x 2\. Minuntion. Mrs. Gray's Collection. 



Illaenus, sp. ind. 73. 



13. Head-shield. Nat. size. Craighead. Mrs. Gray's Collection. 



