31 



in reality constructed upim the very same tyjje as in tlie true Lysianassidte, 

 and in some (if the hitter, for instance Acidostoma (see PL 14, tifj-. -J) the 

 agreement is quite unmistakahle. As to the anomalous ap]iearance of the 

 anterior gnathopoda, Dr. Bovallius has shown this to he merely due to a 

 peculiar torsion of the outer part of the leg, wherehy the hand hecomes ([uite 

 inverted in tlie adult animal, whereas in the young these limhs exhibit a far 

 more normal ai)pearance, nearly agreeing with that met with in the genus 

 Normania (see PI. 13, fig. 1). On the other hand the posterior gnathopoda 

 are indistinguishable, both as to form and structure, from those in tlie tyiiical 

 Lysianassidse. Finally the nrosome, which in Boeck's opinion, is evidently 

 Hj'periidean in character, essentially differs by lieing divided into 3 distinct 

 segments and liv the last pair of uropoda liaving a distinct terminal joint, as 

 is the case in tlie greater part of the typical (Tammaridea. Moreover, the 

 whole exterior habitus and the structnre of Ijoth tlie antennse and the legs 

 pretty well agrees with that met with in the Lysianassidse, no essential 

 difference whatever being found to exist. 



1 Trischizostoma Raschi, (Boeck). 

 (ri. 12). 



Trischizostoma Raschi, Boeck, Crust. Ampliip. boi'j iV: arct. [i. 11. 



Body glabrous, moderately slender, with the liack evenly vaulted. 

 Cephaloii rather short, narrowed inferioiiy, frontal ])rqjection horizontal, 

 obtuse at the tip. Coxal plates scarcely as deep as the body, 1st pair very- 

 small and ])artly covered by the 2n(l; the latter greatly ex])anded iiiferioi-ly, 

 jutting out l)oth anteriorly and posteriorly as a triangular lobe; the two 

 succeeding ])airs almost eiiual-sized, ol)lii[uely oval, 4th jiair truncated at the 

 ti]i and deeply emargiiiated postei'iorly to receive the 5th one, the posterior 

 lolje of which is much deeper than the anterior; the 2 posterior i>airs rather 

 small. Last pair of epinieral ]ilates of inetasome nearly riglit-angled. First 

 segment of urosome deeply impressed at the base dorsally. Eyes successively 

 expanding superiorly, iiearh' confluent, though separated by a narrow stri])e 

 above in the middle. Superior antennse a little longer than the ceplialou, 

 1st joint of the peduncle much longer than the other 2 combined, llagellum 

 'J-aiticulate, with the 1st joint very large, accessory appendage about the 

 length of the latter, triarticulate, the 2 outer joints very small. Inferior 

 antenna^ twice the length of the superior, pennltimate joint of the peduncle 

 the largest, flagelluni composed of about 24 articulations. Anterior gnatlio- 

 ])n(la with the propodos greatly iiiHatrd. i-diimli'il triangular, tnrniiiig anteriorly 



