CRUSTAGl 



Class I. — Ci;r-T,\.d^P (H Shrimps, I. 



General Characters of Crustaceans. — The I forms 



<>f t: .• craw-fish, ! which the 



strident should carefully examine, as from them a general 

 knowledge of the claflf which varies greatly in form in the 

 ent <'!<:< :-. may be obtained. The follow: >unt 



of the lobs 1 serve 11 for tw-fish, 



which abounds iu the rivers and strcan Central j 



\\ cstern S 



The lobster's body E which in ll 



men are seen to form a complete ring, bearing a pair of jointed ap- 

 pendages. The abdomi i One 



94 liould I 



arated from the others by ll nt, 



in order to observe the i • r- ^ fMl i 



ti >a of the li gs. 1. ■ b s< _• • i ^.'~ , 



but a single pair of . and i; 



i- a irencral rule that in the Arthr<>p"i!s |]JB* ^ J 



-ii. rut bears but a - S 



of appendages. T >miual f< ~ ' 



,,,... ■• .i ■ -Mandil 



are called ■swimmercts; the; Boman 



narrow, slender, divided at the eud palpus. 



into two or tliree lobes or portl 



and are used for swimming, as well as in the female for enrr 



the eggs. The first pair tdcr in the femn 94, 



livided, while in the male (Fig. 94, B | they are much la 



and aid in reproduction. The sixth b< gmenl 



paddle-like appen while the seventh .- forming thi 



of the body and called the " telson," bears n.> a] 



gum alone of the segment. Turning now to tin 



thorax, we see that there are two pairs of antenna;, the 



the most anterior; a pair of mandibles with a palpus, situated on 



each side of the mouth; iwo pairs of mas 



which are fiat, divided into loins, and of unequal size; three pah 



foot-jaws (maxillipcdes), which differ from the maxillae in having 



gills like those in the five following pair- of 1< l:s.* T thus 



* Tho stwjei its limbs in a boiled flsli. and 



compare them with the cute. He will (lad the < 



