EYE-LASHES AND EAK-SLITS 181 



longing to either the Phyllobranchiata or to the Tricho- 

 branchiata, as the plumes consist of two rows of long 

 slender filaments so closely impacted together that they 

 are flattened into plates,' and elsewhere he remarks that 

 ' in some genera, as in Thalassiiia, the branchi^ are both 

 foliaceous and filamentous.' 



Family 1. — Thalassinidce. 



The carapace is dorsally flattened, with rostrum. The 

 eyes are small, the eye-stalks cylindrical. The first pair of 

 antennge have the flagella long ; the second have no scale 

 on the second joint. The first pair of trunk-limbs are un- 

 equal, imperfectly chelate, the last joint or finger being 

 longer than the thumb ; the four following pairs are 

 simple, with the terminal joint long. In the pleon the 

 uropods, that is, the appendages of the sixth segment, are 

 slender and acute, the outer branch not transversely 

 sutured ; the telson is also without suture, obtusely pointed. 

 The branchiae are complex. 



The family includes but one genus. 



Thalassina, Latreille, 1806, has the characters of the 

 family. It contains but few species, perhaps only the type 

 ThalassiTiM anomalus (Herbst, vol. 3, part 4, p. 45, 1804), 

 which Latreille in 1806 called Thalassina scorpionoides. 

 This is widely distributed in the Pacific. A specimen nine 

 inches long was procured by the Challenger at Kandavu, one 

 of the Fiji Islands. Some points of Mr. Spence Bate's 

 minute description will teach the student what to look for 

 in various other species of the Macrura. For the small 

 sub-conical eyes imperfect orbits are formed by help of the 

 rostrum and depressions in the upper surface of the first 

 antennae. Projecting forwards from the rostrum and 

 upper part of the orbit and backwards from the antennae 

 are numerous hairs which form for the eyes a protecting 

 fringe, which is in Greek the blephdris in English the 

 eye-lashes. The basal joint of the first antennae has a 

 long triangular slit, the opioning of the ear, which is thus 

 described : — ' The auditory apparatus consists of a large 



