Numerous other works in English and French have been published on Tunisia from the tourist's point of view; the best of these is by Douglas Sladen, Carthage and Tunis (2 vols., 1908).
(See further AUSTRALIA.) See Douglas Sladen, From Boundary Rider to Prime Minister 1916).
Sladen states that a queen belonging to the virginalis form of Bombus terrestris often invades a nest belonging to the lucorum form, kills the rightful queen, andtakespossession of the nest, getting the lucorum workers to rear her young.
P. Sladen and H.
Lyman ("Challenger"), Sladen ("Astrophiura," Ann.
Carpenter, Sladen and others.
P. Sladen, who divided the Euasterida into two orders: (I) Phanerozonia, with marginals large and highly developed, the supero-marginals and inferomarginals contiguous, with papulae confined to the dorsal surface, with ambulacrals well spaced and usually broad, adambulacrals prominent in the mouth-skeleton, with pedicellariae sessile; (2) Cryptozonia, with marginals inconspicuous and somewhat atrophied in the adult, the supero-marginals separated from the inferomarginals by intercalated plates, with papulae distributed over the whole body, with ambulacrals crowded and narrow, either ambulacrals or adambulacrals prominent in the mouth-skeleton, with pedicellariae stalked or sessile.
P. Sladen, "Homologies of the Primary Larval Plates in the Test of Brachiate Echinoderms," Quart.
Sladen, Queen-rearing in England; S.