882 THE AMERICAN NATURALIST. (Vor: XXXII. 
The entoderm cells arrange themselves as a one-layered epithelium. 
The body consists of a primary cephalic plate, a primary anal piece 
(telson), and the metameres between these, as follows: (1) an anten- 
nular segment ; (2) antennal segment ; (3) intercalary segment ; (4) 
mandibular segment; (5 and 6) two maxillary segments ; (7) seg- 
ment of the maxilliped ; (8—28) body segments ; (29 and 30) genital 
segments. These are shown not only by the external appearances 
but by the ganglia as well. The protocerebrum consists of (1) the 
archicerebrum arising in the clypeus ; (2) two pairs of ganglia in 
the primary head plate ; (3) the optic ganglia (which arise by delami- 
nation) ; (4) a pair of ganglia in the antennular segment. ‘The anten- 
nal? segment gives rise to the deutocerebrum, while the intercalated 
segment gives rise to the tritocerebrum. There is no ganglion in the 
telson. The sympathetic system arises from the fore-gut; the dorsal 
cardial nerve from the mid-dorsal ectoderm. The head or salivary 
glands are purely ectodermal and cannot be compared to nephridia. 
Ccelomic cavities occur in each segment (thirty pairs), the cephalic 
plate and telson excepted. The unpaired gonad and its duct are 
paired in origin, and their cavities arise from the ccelom, and in the 
adult traces of the left of the two primary ducts can be found. The 
genital ducts have, as in Hexapods, an ectodermal termination, from 
which arise the two paired accessory glands. 
` These facts go to show a close relationship to the Hexapods, and to 
support the view that chilopods and diplopods are, at least, very 
remote from each other; in other words, that a natural group of 
myriapods does not exist. Lae 
The Aarbog, of the Bergen (Norway) Museum for 1897 maintains 
the high standard of this publication in the past. Among the papers 
which it contains are the following: R. Collett, an account of the 
beavers in Norway, illustrated by a dozen half-tone plates from 
photographs. The number of beavers now existing in Norway is 
estimated at about 100. Collett found no parasites on any of the 
specimens which he examined. K. F. Koldrup reviews the rocks of 
the Ekersund-Soggendal region. James A. Grieg describes a specimen 
of the cetacean Mesoplodon bidens, stranded on the Norwegian coast 
in 1895, with notes on other Scandinavian specimens. He contrib- 
utes in a second paper notes on other cetaceans. R. Collett describes 
and figures a hybrid between Zagopus mutus and Tetrao tetrix. K. E. 
Schreiner describes the eyes of several free-living chaetopods. 
1 Heymons says antennular segment, evidently a slip of the pen. 
