SCIENTIFIC SUMMARY. 
223 
'when the salivary glands of insects are not diverted from their primitive 
function to become silk or poison glands, they secrete a neutral or alkaline 
liquid, possessing, at least as regards one pair, the property characteristic of 
the saliva of vertebrate animals of rapidly transforming starch matters into 
soluble and assimilable glycose. The change is effected in a posterior 
dilation of the oesophagus. At this place results in the carnivorous insects 
a transformation of albuminous matters into soluble substances like peptone, 
and in vegetable-feeding species an abundant production of sugar out of the 
starchy matter eaten. When digestion has taken place in the oesophagus, it 
is submitted to an energetic pressure in the gizzard or proventriculus, which 
is armed with teeth. It thus seems that this is not an apparatus for crush- 
ing the food, but for expressing the liquid from the food triturated by the 
jaws. In the stomach, or middle intestine, as Plateau calls it, the food is 
again submitted to the action of an alkaline or neutral liquid secreted by 
local glands, present in the Orthoptera, or by a great number of small 
glandular cseca as in many beetles, or by a simple lining of epithelial cells. 
This fluid has no analogy with the gastric fluid of vertebrate animals. Its 
function differs according to the group to which the insect belongs. In the 
carnivorous beetles it makes an emulsion of the greasy matters; in the 
Hydrophilid beetles it continues the conversion of starch into glycose, begun 
in the oesophagus. In the caterpillars of the butterflies and moths it 
determines a production of glycose and makes an emulsion of greasy matters, 
and in the grasshoppers no sugar is formed in the intestine, as this material 
is produced and absorbed in the oesophagus. 
The Corals of the Galapagos Islands have been investigated by Count 
Pourtales, who has published the following account (“ Silliman’s American 
Journal”) : — The Galapagos Islands are, as is well known, an important 
point in the geographical distribution of corals, being almost exactly on 
the boundary of the coral-producing part of the Pacific Ocean, and that 
portion which is destitute of them on account of the low temperature of 
the water. All the writers on the subject have placed this group of islands 
in this latter portion. During the visit of the United States Coast Survey 
steamer Hassler, a number of specimens of corals, of which the following is 
the list, were picked up on the beaches of several of the islands : — Ulangia 
Bradleyi, Verrill, Indefatigable Island; Pavonia gigantea , Verrill, James 
Island; Pavonia clivosa, Verrill, Indefatigable Island; Pavonia , sp., James 
Island ; Astropsammia Pedersenii, Yerril ; Pocillipora capitata, Verrill, Jervis 
and Charles Islands ; Porites, sp. The undetermined Pavonia is a massive 
species with larger calicles than those of the two other ones, and more 
porous and lighter. The specimen is too much rolled for nearer determina- 
tion. The Porites is massive also, and in the same condition. The species 
are all, or nearly all, identical with those found at Panama. They are 
mostly reef-builders, but here live probably isolated and at a certain depth, 
having never been observed in situ. In individual growth they are fully 
equal to those from more favoured localites, the rolled pieces of Pavonia mea- 
! suring six or seven inches in diameter, thus indicating masses of considerable 
size originally. They are not confined to the northernmost islands of the 
group, where we should more naturally look for them, from the greater 
proximity to the warm current ; but, as the list shows, a Pocillipora was found 
