HOPLOCARIDA STOMATOPODA 



141 



thoracic legs inside, while the abdomen is pushed out through 

 an opening of the Pyrosoma case behind, and by its alternate 

 flexion and extension drives the boat forwards, the water being 

 thus made to enter at the front aperture and supply the female 

 and her brood with nourishment. 



DIVISION 



HOPLOCAEIDA. 



The carapace leaves at least four of the thoracic somites 

 distinct. The eyes are pedunculate. The mandibles are without 

 a lacinia mobilis ; there are no oostegites, the eggs being carried 

 in a chamber formed by the maxillipedes. The hepatic caeca 

 are much ramified, the heart is greatly elongated, stretching 

 through thorax and abdomen, with a pair of ostia in each 

 segment. The spermatozoa are spherical, and there is a compli- 



cated and peculiEir metamorphosis. 



Order. Stomatopoda. 



The Stomatopoda are rather large animals, occasionally reach- 

 ing a foot in length, all of which exhibit a very similar structure ; 

 Sqidlla mantis and ^S*. desmaresti are found on the south coast of 



A.2 



Fig. 98.--Lateral view of SquiUa sp., x 1. A.l, A.S, 1st and 2ud antennae ; Ab.l, 

 ]st abdominal segment; Ab.6, 6th abdominal appendage; G, cepbalothorax, con- 

 sisting of the head fused with the first five thoracic segments ; E, eye ; M, ind 

 maxillipede ; T, telson. (After Gerstaecker and Ortmann.) 



England not very frequently ; but they are very common in the 

 Mediterranean, living in holes or in the sand within ' tlie littoral 

 zone of shallow water. They differ from all the other Mala- 



