MALACOSTRACA LEPTOSTRACA 



I I I 



SEEIES 1. LEPTOSTEACA. 



Division. Phyllocarida. 



The small shrimp 

 burrowing in the 

 superficial layers 

 of sand in the 

 littoral and some- 

 times the deeper 

 regions of most 

 seas, has been re- 

 garded, ever since 

 its anatomy was 

 made out l^y Claus,^ 

 as a connecting 

 link between En- 

 tomostraca and 

 Malacostraca, and 

 has been placed in 

 a separate group 

 Leptostraca. 



The segmenta- 

 tion of the body 

 is Malacostracan, 

 save that two extra 

 segments are pre- 

 sent in the abdo- 

 men, and the paired 

 compound eyes are 

 borne upon stalks. 

 The eight thoracic 

 limbs are all very 

 similar ; they are 

 built on the typi- 

 cal biramous plan, 

 and each carries a 

 bract ; they have 

 been compared, owing 



-like Crustacean Nelalia, 'which is found 



A.1 E 



Fig. 76. — Nehalia geoffroyi, 

 9, X 20. A.l, A. 2, 1st 

 aud 2n<l antennae ; Ah.l, 

 Ab.6, 1st and 6th abdo- 

 minal appendages ; A.G, 

 imtennary gland ; C, half 

 of caudal fork ; Ji, eye ; G, 

 ventral gani,dionic chain ; 

 /y, heart ; /, intestine ; L, 

 upper liver-diverticuliim ; 

 M, adductor muscle of 

 halves of carapace ; MX, 

 palp of 1st maxilla ; 

 0, ovary ; Ji, rostrum. 

 (After Claus.) 



to their flattened, expanded shape, to the 



1 Claus, Arb. Inst. JVkn, viii., 1889, p. 1. 



