69 

 34. Psathyrocaris fragilis, Wood-Mason. 



Psathyrocaris fragilis, Wood-Mason, Ann. Mag. Nat. Hist., Feb. 1893, p. 171, pis. x. xi : Caullery, Caudan Crust. 

 in Ann. Uoiv. Lyon, 1896, p. 374, pi. xiv. figs. 12-15. 



Illustratiohs of the Zoology of the Investigator, Crustacea, Plate LII. Fig. 5. 



Kostrum horizontal, reaching nearly to the end of the eye and continued 

 backwards as a gastric crest : its ventral edge forms a convex lamina, its dorsal 

 edge is armed with some minute teeth as is also the anterior end of the gastric 

 crest. 



From the orbital angle a ridge takes a sinuous course backwards almost to 

 the posterior border of the carapace, giving off in the hepatic region a branch 

 that runs obliquely backwards towards the lower border of the carapace. The 

 6th abdominal somite is slender and twice as long as the 5th. 



Eyestalks moderately depressed : eyes nearly black, more ventral than dorsal 

 in position. 



The antennular scale reaches nearly to the end of the 2nd joint of the 

 antennular peduncle and is fluted and twisted. The antennal scale is about half 

 the length of the carapace proper : it has a midrib, and its outer border also is 

 thickened and ends acutely. 



The external maxillipeds reach a little beyond the antennal scale : their 2nd 

 joint is thin and broadish, the next three joints are slender. 



The 1st pair of legs are not quite half the total length of the body : their 

 hand, in which the fingers are less than two-thirds the length of the palm, 

 is not quite a third their total length, and the fixed finger alone has pectinate 

 teeth : all their joints are smooth and their exopodite is small. 



The 2nd pair are about as long as the whole body without the telson : their 

 hand, in which the fingers are not much shorter than the palm, is more than 

 two-fifths their total length : all their joints are smooth and their exopodite is of 

 good length. 



The filiform 3rd and 4th pair are actually longer than the 1st pair : though 

 their exopodites are very long they are not so long as the endopodites. 



The 5th pair, which are about as long as the carapace, are fairly stout : the 

 posterior border of their propodite is setose, especially at the distal end, and the 

 setose dactylus, which appears to be permanently more or less flexed, seems to 

 be capable of complete flexion on to a special tuft of seta? at the far end of the 

 posterior border of the propodite. 



The filiform exopodites of the first five pairs of abdominal appendages are 

 infinitely longer than the endopodites : the exopodites of the 1st pair are about 

 as long as the distance between the tip of the rostrum and the 5th abdominal 

 somite. 



In life the body is of a ruddy colour. 



