108 
POPULAR SCIENCE REYIEW. 
nymphse are preserved. These undergo a change of form and become 
clothed with a cuirass which completely disguises but at the same time pro- 
tects them ; moreover, they acquire a sucker by which they are enabled to 
adhere firmly to any passing object, such as flies, spiders, myriapods, and 
insects of all kinds, or even to quadrupeds, by which they are transported to 
places they could never reach by their own unaided efforts. If they find a 
suitable locality, as on a young mushroom or a mass of decomposing sub- 
stance, the little acaridan quits its temporary host and its hypopial form and 
reassumes the original tyroglyphic one. Under the influence of abundant 
food it rapidly enlarges, becomes a sexual adult, and in forty-eight hours a 
new colony appears.” 
The Circulation in a species of Delphinus. — This is thus described by Dr. 
H. C. Chapman, in a recent paper in the “ Proceedings of the Academy of 
Natural Science of Philadelphia.” He says that the circulation of the blood 
offers us interesting peculiarities in the existence of vast plexuses, the 
breaking up of the brachial and other arteries into rete mirabile. Of the 
distribution of the arteries, the intercostals are the most remarkable. They 
are developed, twisted, interlaced to such an extent, as to give the appear- 
ance of a large thoracic gland, formerly in fact described as such. By this 
arrangement of the intercostal and other arteries there are formed large 
reservoirs of arterialized blood, enabling the animal no doubt to remain sub- 
merged for long periods of time. The dividing of the brachial artery into 
numerous branches has been explained by reference to the shortness of the 
pectoral fin or upper extremity, but this distribution has been observed in 
certain Lemurs and other animals, in which the upper extremity is well 
developed. 
The Abdomen of the New Zealand May-fly. — This is certainly a curious 
organ. It is described by Mr. M‘Lachlan, who, in a recent number of the 
u Entomologist’s Monthly Magazine,” in describing Oniscigaster Wakefeldi , 
a new genus and species of Ephemeridae, from New Zealand, says that the 
extraordinary abdomen of this genus, if considered apart and without regard 
to the rest of the body, might almost be pardonably mistaken for that of 
seme Myriapod, without the legs, or of a crustacean. Eemales only have 
been discovered, and till we gain some knowledge of the characters of the 
male, the affinities must remain somewhat uncertain. Mr. Eaton has 
pointed out in his Monograph on the Ephemeridae that a tendency to 
lateral production of the terminal segments of the abdomen is shown in 
several genera, but the amount of expansion hitherto known is infinitesimal 
compared with that present in this new form. For actual affinity in this 
respect one must look to the aquatic stages of some forms ; and if the asser- 
tion by MM. Joly that the so-called genus of branchicpod Crustacea Proso- 
pistoma Latreille is, as appears probable, in reality only the aquatic 
condition of an Ephemerid, we have in the u Binocle a queue en plumet ” 
the nearest ally, so far as regards abdominal structure, to O. Wakefieldi. 
Poes a species of Bird always Build the same Nests ? — An article in our 
present number shows that they do not. But we have additional evidence 
in support of this idea in the following remarks, which were recently made 
to the Natural Science Academy of Philadelphia (September 23rd), by Mr. 
Gentry, who has been examining the nests of Vireo solitarius. He states 
