Guide to Crustacea. 
36 
Sub-class V. MALACOSTRACA. 
The body consists of nineteen limb-bearing somites (or twenty, 
if the eye-stalks be reckoned as appendages). A thorax of eight 
and an abdomen usually of six somites are sharply distinguished 
by the character of the appendages. 
This sub-class is much larger and more varied than any of the 
others. It may be divided into two series as follows : — 
Series 1 . Leptostraca (Abdomen of seven somites). 
Division 1. Phyllocarida. 
Series 2. Eumalacostraca (Abdomen of six somites). 
Division 2. Syncarida. 
,, 3. Peracarida 
,, 4. Hoplocarida. 
,, 5. Eucarida. 
Fig. 15. 
Nebalia bipes, female, from the side (enlarged), a.', Antennule; a.", antenna; 
ab.'-ab.*, the abdominal limbs ; ad., the adductor muscle joining the two 
valves of the shell; /., the caudal fork ; p., palp of maxillula ; r., rostral 
plate ; t., telson ; 1-7, the seven somites of the abdomen. (From 
Lankester’s “ Treatise on Zoology,” after Claus.) 
Division 1.— PHYLLOCARIDA. 
The carapace is bivalved, enveloping but not coalescing with 
the thoracic somites, and bearing in front a movably articulated 
rostral plate. The eyes are stalked. The last somite of the abdomen 
has no limbs, but the telson carries a pair of appendages forming the 
“ caudal fork.” The thoracic limbs are flattened and leaf-like. 
The existing species belonging to this division are few in 
number but are very widely distributed in all seas. Nebalia bipes, 
