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POPULAR SCIENCE REVIEW. 
Crustacean proper (Cyclops). The main object of these 
figures is to demonstrate the fact that, however dissimilar in 
their adult forms may be the representatives of the various 
divisions of the Crustacean stock Stammform ”), they have 
a striking similarity, making allowance for difierences in 
minor particulars, in their larval stage. 
Fig. 10. Complementary male ” of Scalpellum Vulgare attached over fold 
in “ occludent margin ” of the scutum of the hermaphrodite. 
Reduced and modified from fig. 37, tab. x. of Cams’ leones 
Zootomicse,” taken from fig. 9, pi. v. of Darwin’s mono- 
graph. (o) Orifice of sack of male, (p) Spinous projections 
above the rudimentary valves, (c) A transparent border of 
chitine — supporting long spines — which forms a border to 
the occludent margin” of the scutum of the hermaphro- 
dite. (d) Depression for the adductor scutorum muscle of the 
hermaphrodite. 
At the top of the figure are represented, as seen through the 
whole thickness of the animal, the prehensile larval antennae. 
For comparison with the above, see the figure of the male of 
Scalpellum regium, given in one of Prof. Wyville Thomson’s 
Notes from the Challenger,'^ in ‘^Nature,” August 28. 
1873. 
