THOMPSON : A RARE THALASSINID. 
13 
The propodi of the posterior pereiopods are longer relatively to the 
whole limb than in the adult. The gills are as in the adult animal, 
but all the mastigobranchs, excepting the most anterior, are more 
slender, and the posterior podobranchs are small. The plates of the 
gills are linear or linear-oval. The pleopods are present on seg¬ 
ments two to five and their rami are less lanceolate than in the 
adult (pi. 2, fig. 29). The uropods have narrower rami than in the 
adult and the transverse suture of the inner ramus is fiexed. The 
material did not permit a study of the internal anatomy. 
Probable Affinities of Naushonia. 
The larvae of Naushonia find their nearest counterpart in those 
of another Thalassinid, Calliaxis adriatica (Heller). The young of 
this species have been described and figured by Cano (’ 91 ) and 
Claus (’ 84 ). Not only is their general form very much like that of 
the Naushonia young, but thev also resemble them in all important 
anatomical details. The presence of a ventral gland with the same 
relations as in Naushonia is especially important in this connection. 
asymmetrical and have a similar 
relation to the sides of the body, the conical on the right, the 
arcuate on the left. The chief points of difference between the 
Calliaxis and the Naushonia larvae are found in the less arcuate 
rostrum of the Adriatic form which is not recurved at the tip; the 
relatively longer “neck” (if we may wholly credit Cano’s figures, 
which seem rather crude, this equals the carapace in length in stage 
“A,” exceeds it in “B,” and is twice as long in “C”); the presence 
of hooks on the angles of the sixth as well as the anterior abdominal 
segments in the my sis stages (Cano) ; the more spatulate telson of 
the “mysis” which recalls the shape of the telson in larvae of Gebia 
(Sars, ’ 84 ); the absence of a functional exopod on the fourth 
pereiopods; the more rapid development of the green gland and the 
greater size of the ventral gland. None of these, however, are 
characters which detract from the essential likeness between the 
two forms. 
The succession of the stages in Calliaxis is not clear. Cano 
apparently records live preadolescent stages, figuring the first (“A ”), 
third (“B”),and fifth (“C,” “mysis”). Of these, “A” corresponds 
The mandibles also are similarly 
