24 JJE. H. J. HAKSElSr ON EATHTNOMFS GI&AKTEUS- 



fortes dents posterieures, permet plus surement de distinguer les 

 Bathyuomes des Cirolanes, d'antant que cette piece est depourvue 

 des soies marginales qu'on observe dans la plupart des Cirolanes, 

 si non chez toutes." But Bathynomus gig aniens is not without 

 setae at the posterior margin of the last abdominal segment. 

 The large and beautiful figure on pi. 2 in the French work, o£ 

 the animal seen from below, shows fine and short hairs between 

 the marginal processes, and this is quite correct. On the lower 

 side along the margin between the processes mentioned is 

 observed a fine transverse furrow, in which a row of thin plumose 

 setie are inserted ; the longest of these setae I have found between 

 the fourth and the fifth process — the median one taken as the 

 first — and some of them measured about 1"5 mm. in length. A 

 large number of these submarginal setae have been broken off in 

 our specimen, but on a closer inspection the farrow mentioned 

 and some of the setae are everywhere distinctly seen. It may be 

 added that setae at the hind margin exist in all species of 

 Cirolana. 



Pleopoda. — In ' Zoologischer Anzeiger,' nos. 420-421, 1893, I 

 wrote (§ 13) : " Es folgt aus .... dass man drei Glieder im 

 Sfamm von alien gespalteteii Gliedmassen hei den Crustaceen als 

 ein primares Verhdltnis annelimen muss " ; and I mentioned the 

 existence of these three joints in the thoracic appendages of the 

 Phyllopoda, in the natatory limbs of Argulus, in the antennae 

 and mandibles of certain pelagic Copepoda, in the antennae and 

 the thoracic legs of Nehalia, in the antennae of Mysidce verae and 

 of some Isopoda, in the maxillulae and maxillae of nearly all 

 orders of Malacostraca. Now Bouvier writes (p. 154) on Bath. 

 giganteus : " Les pleopodes (pi. 6. figs. 1-5, 7) ont conserve 

 la structure normale des appendices des Crustaces, en ce sens 

 qu'il se composeut (figs. 1, 4) d'une hampe ou sympodite de 

 trois articles, et de deux lames terminales, endopodite et exopo- 

 dite " — and next he describes these parts. The gigantic animal 

 is an excellent object for the study of the joints in the sympods 

 of pleopoda, while such joints in animals of normal size are 

 difficult to discover and especially difficult to judge of with 

 certainty. I have examined the pleopoda of Bathynomus, and 

 can only confirm T ^uvier's interesting discovery : it is the first 

 time that three joints have been pointed out in the peduncle, the 

 sympod, of abdominal legs. Bouvier says that the interior lobe 

 of the sympod '" est cilie de puissantes soies," and they are drawn 



