360 Endocranium and Maxillary Suspensorium of the Bee, [May, 
of the maxille. This shows clearly how the excavation and the 
rods and connecting sheets arise by an involution of the cranial 
wall, with thickenings in special tracts. 
The large black ant (Formica pennsylvanica) carries our 
thoughts still further. It has only one basi-cranial rod (Fig. 4, 
Ms), extending forward above the basi-cranial wall (which is not 
excavated). This is derivable from the case of the bee, on the 
supposition that the basal rods and the margins of the basi-cran- 
ial involution have approximated medially so as to coalesce. The 
ant’s suspensorium has a medi-suspensorial pair of maxillary 
rami (MR), as in the bee; but its labial rami are so small as to be 
nearly obsolete. Its basi-labium (BL) and its medi-labial case 
(mL) are much as in the bee; but its disti-labial parts are con- 
densed. 
The series of gradations thus attained holds out inducements 
to pursue the subject, and we may perhaps see the beginning of a 
new line of discovery in this field, Compare, for example, the 
maxillary adjustments of the cockroach with those of the insects 
already described, Here again Mr. Huxley is less happy than 
usual in ‘his anatomical descriptions. He states that the basal 
piece or cardo of the maxilla of the cockroach is connected with 
a thin band which runs round the posterior margin of the epi- 
cranium and is firmly united with it only on its dorsal side. He 
does not indeed represent the maxille as directly inserted in the 
back of the skull, but he regards them as attached to a band which 
is itself attached to the back or dor- 
sal aspect of the skull, and which he 
is thus compelled to consider a por- 
tion of its exoskeleton. This view, 
if sustained, would clash with the 
mode of suspension in the bee, where 
the maxilla have been found to have 
endocranial connections with the base 
or ventral side of the skull. 
A careful examination of the con- 
Fic. 6.—Endocranium and max- nections‘ in the cockroach, proves, 
aD cach (Porialancie orkeneetay, HoNevens that the: cardines OF sg 
EC, endocranium; CA, cardo. Other maxillz are inserted ina ridge which 
references as in Fig. 5. crosses the basis-cranium in front of 
the occipital foramen (though a slender ridge runs from this part 
