392 



THE INVERTEBRATA 



The 2nd thoracic limb bears a large, raptorial subchela. The ali- 

 mefitary canal has a rather simple proventriculus and a large branched 

 "liver"; the latter and the gonads extend along the large abdomen. 

 In the nervous system eight pairs of ganglia are fused as the sub- 

 oesophageal ganglion. The heart is very long, reaching from the 

 head to the fifth abdominal somite. The excretory organs are maxillary 

 glands. The larvae are pelagic and of the same general type as the 

 Zoaea but with a peculiar facies of their own (Fig. 266 D). 



The members of the subclass are all marine, and for the most part 

 live in burrows. 



Squilla (Fig. 268) occurs in British waters. 



Subclass SYNCARIDA 



Malacostraca without carapace; with eyes stalked, sessile or absent; 

 most of the thoracic limbs provided with exopodites and none of them 

 chelate or subchelate ; no oostegites ; a tail fan ; and simple coeca on 

 the mid gut, 



A small group of freshwater malacostracans with a combination of 

 features which forbids their inclusion in either of the other subclasses. 

 In typical genera, they possess most of the features of the caridoid 



VIII 



n cgr 



Fig. 269. Anaspides tasmaniae, x 3. From Woodward, cgr. mandibular or 

 "anterior cervical" groove; ii, viii, second and eighth thoracic somites; 

 I, 6, first and sixth abdominal somites. 



facies except the carapace ; and the relatively slight differentiation of 

 thorax from abdomen is a primitive character possessed by no other 

 member of the class. 



Anaspides (Figs. 223, 269), from pools at 4000 feet in Tasmania, is 

 a normal member of the group. 



Bathynella, from subterranean waters in Central Europe and Eng- 

 land, small, degenerate, and eyeless, has various limbs reduced or 

 absent and the first thoracic segment free. 



