MALACOSTRACA LEPTOSTRACA 



I I I 



SEEIES 1. LEPTOSTEACA. 



Division. Phyllocarida. 



The small shrimp -like Crustacean Nehalia, which is found 



A.1 



..A.a 



L 



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 by 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 to their flattened, expanded shape, to the 



1 Glaus, Arb. Inst. IVicn, viii., 1889, p. 1. 



Fib. 76. — Nehalia geoffroyi, 

 ?, X 20. A.l, A.S, l.st 

 and 2ii(i antennae ; Ah,l^ 

 Ab.6, 1st and 6tli abdo- 

 minal appendage-s ; A.G, 

 antennary gland ; C, half 

 of caudal fork ; £■, eye ; G^ 

 ventral ganglionic chain ; 

 11, heart ; /, inte.stine ; L, 

 npper liver-diverticuhim ; 

 M, adductor muscle of 

 halves of carapace ; MX, 

 palp of 1st maxilla ; 

 0, ovary ; R, rostrum. 

 (After Clans.) 



