372 GEOLOGICAL SURVEY OF THE TERRITORIES. 
appendages in general protopoda, the term “‘cephalopoda” being other- 
wise in use. The thorax of insects and of most of the crustacea might 
be designated the Banosome (favo, to walk, locomotion), and the tho- 
racic appendages Benopoda, the segments being called bcanomeres ; 
while Urosome might be applied to the abdomen, the abdominal segments 
being called uromeres. Westwood’s term uropoda might be extended so 
as to include all the abdominal appendages. The term gonopoda we 
have suggested for the external organs of the Decapods concerned in 
reproduction, which are simply modified uropoda. The long, slender, 
antenna-like anal appendages of the cockroach, mantis, Wc., correspond. 
ing to the anal cerci of Acrydii, may be designated as cercopoda, and 
this term might be applied to the terminal pair of uropoda of the Phyl- 
lopods, 2. ¢., the jointed, slender, spinulose appendages of Apodide, or 
the unjointed appendages of the Branchipodide. 
The segments of the body.—The Phyllopoda are exceptional to other 
Crustacea in having an indefinite number of segments composing the 
body, and in having in one family (Apodide) more than one pair of ap- 
pendages to an arthromere. While the normal number in the Decapoda 
3s 20, in the Phyllopods it varies from 14 in Limnetis to47in Apus. The 
following table shows the number in different genera of American aD 
cies : 
>) ta) =| n 
2B < 3 3a 
ay 2 o 5 SS 
ea} o 7 a 0) 2a 
=e) 2 & = a zl D Q 
aa I I a ir > | 5 s 
.S 5 ZI A rs) Q & 
A $ S g & 2 oO ° 
<q =p eel | 4 4 a a4 
Pim etiSy is case Serpe Mu oe a 2 1 Die frsiavec itr 12 (-14) 0 1 17-19 
Sterna seu sso eho eon el Sake erence cere 2 1 2 Eek ee 23-27 0 1 29-33 
J Byes b debt ee See OR eLrenes Me care at eo ee tee eee cic 2 1 Qi ee 1 22 0 1 28 
PACU Sioa ate cinyec mensch Seis deletes ere etalon ere paele *2 1 1 t1 27 (60 pairs |32 (14) 1 47 
limbs). 
HAT CE TIN A May Se BNA aise JAE eRe ee 2 1 2 0 11 8 a 25 
‘Branchinectay sae wseea osc ce ccc ene 2 1 2 0 11 9 1 26 
‘Bran chipuswesece!-a stone eee sesso ee 2 1 2 0 11 9 1 26 
*Second antenne sometimes wanting.  tThe endite wanting in the American species of Apus. 
In an Apus lucasanus 42 millimeters in length there are 60 pairs of 
legs behind the maxillipedes. There are 42 segments behind the max- 
ilhipedal segment, including the telson, and 27 limb-bearing segments, 
or 60 pairs ‘of legs to 27 segments, the average being 2.% appendages to 
each leg- bearing segment. On the first eleven leg bearing arthromeres, 
or the 10 thoracic (beenomeres) together with the first abdominal arthro- 
mere there is but a single pair of appendages to a segment, so that there 
are 49 pairs of abdominal appendages to 16 arthromeres, or og pairs of 
himbs on the average to each abdominal arthromere. The fourteenth, 
fifteenth, and sixteenth pairs are situated on two arthromeres, and 30 
on with the succeeding until the limbs become more numerous. On the 
two arthromeres before the last leg-bearing one there are 12 pais of 
appendages, or 6 to each arthromere 
This irrelative repetition of arthromeres i is only paralleled in one other 
Branchiate group, the Trilobita. In this group the new segments are 
interpolated between the head and abdomen at successive moults, as 
shown by Barrande. 
The grouping of the body segments into a cephalothorax and abdo- 
-men, comparable with those two regions in the Decapoda is but slightly, - 
if at all, indicated in the Phyllopoda. In Linnetis there is no such dis- 
tinction of regions, in Apus the cephalothorax merges insensibly into the 
* 
