504 CRUSTACEA MALACOSTRACA. 



long legs. They are inhabitants of the littoral zone, frequenting tufts of 

 hydroids, polyzoa and algae, among which they lurk motionless. They 

 are often of brilliant colours, harmonizing with the colour of their en- 

 vironment. According to Paul Mayer Caprella dentata is bright green 

 or nearly colourless, according as it lives among algae or hydroids. They 

 progress with a looping movement, like a stick caterpillar, or swim by 

 repeated rapid flexions of the body. The cephalothorax is small. 

 Both pairs of the forward directed antennae are well developed and bear 

 long flagella. The mouth parts do not depart markedly from the usual 

 Amphipod type. The legs of the second thoracic segment, which is more 

 or less closely united with the head, bear grasping hands, as do those of 

 the third pair. The fourth and fifth pairs may be well developed, 

 or vestigial or absent, while the three posterior pairs are long and directed 

 backward, ending in long claws. Branchial sacs on the third and fourth, 

 sometimes on the second thoracic segments. The abdomen is very short, 

 and may be entirely unsegmented. Only 2-3 pairs of stump-like appen- 

 dages are developed on it. Proto Leach ; Caprellina Thorns. ; Protella 

 Dana ; Aegina Kroy. ; Caprella Lam. ; Podalirius and Cercops Kroy. 



FIG. 308. Caprella aequilibra (from Claus, after Paul Mayer). A' epipodial branchiae. ,. 



Fam. 2. Cyamina. " Whale lice." They live attached by their 

 powerful hind legs to the skin of Cetacea, and gnaw out pits in which 

 they lie. Body broad and flat and compressed longitudinally. First 

 antennae directed forwards, with long shaft and short flagellum, the 

 second may be much reduced, four jointed. The mandibles without 

 palps, first maxillae with a short unjointed palp, the second maxillae fused 

 at their bases. Maxillipeds with a single inner lobe and a well developed 

 or rudimentary palp. Second thoracic legs may be slender, the 3rd are 

 powerful, 4th and 5th absent, 6th-8th with powerful hooked claws. The 

 4th and 5th segments bear the long branchial tubes. The wartlike abdo- 

 men is unsegmented, and bears the vestige of a pair of appendages. 

 Cyamus Latr. ; Platycyamus Liitk. 



Order 7. STOMATOPODA.* 



Elongated Malacostraca with short cephalo-thoracic shield which 

 does not cover all the thoracic segments. The five anterior pairs of 



* Besides Dana, M. Edwards and others, compare O. Fr. Miiller, Bruch- 

 stiick aus der Entwickeluiigsgeschichte der Maulfiisser, i and ii, Arch. f. 

 Naturgesch.,xxviii, 1862, and xxix, 1863. C. Claus, Die Metamorphose der 

 Squilliden, Abh. Gottinger Soc., 1872. C. Grobben, Die Geschlechtsorgane 

 von Squilla mantis, Sitzungsber. der k. Akad. der Wissenssch., Wien, 1876. 

 W. K. Brooks, Challenger Report, Stomatopoda, 1886. H, J, Hansen, 



