
AUSTRALIAN CUMACEA, No. 
THE FAMILY DIASTYLIDAE (Parr 2) GYNODIASTYLIS 
AND RELATED GENERA 
By HERBERT M. HALE, Director, SourH AustRALiIAN Museum. 
Fig. 1-60, x 
INTRODUCTION. 
A rew Diastylids have been described which are separated from all others by the 
facts that while the female third maxilliped lacks an exopod the male has no trace 
of pleopods. Species previously known to have these characters in combination 
have been placed in three genera, Gynodiastylis Calman, Allodiastylis Hale and 
Dic Stebbing; the female is unknown in the genotype of the last-named but as 
stated by Zimmer (1914, p. 192) it seems undoubtedly very close indeed to 
(tynodiastylis. 
Australian species belonging to Gynodiastulis and to some other genera with 
subcordate, subcylindrical or short and plump telson show that a reduction to 
vanishing point of the pair of terminal telsonic spines so generally typical of the 
family is not a very significant feature, and by itself cannot be relied upon as a 
generic character; in Allotliastylis and Zimmeriana gen. nov. there is sexual 
difference in the armament of the telson (see also Hale, 1945, p. 179), 
The group under discussion is well represented in Australian waters and 
twenty-six new species, mostly from off the eastern coast, are herein described, 
Although, unfortunately, few of these can be included in them, three new genera 
are proposed in an effort towards preventing Gynodiastylis (which as it is now 
includes a very varied assemblage of forms) from eventually becoming the 
repository for a large number of unclassified species. 
Famity DIASTYLIDAE. 
KEY TO GENERA OF DIC-GYNODIASTYLIS GROUP. 
1. Third maxilliped with ischium greatly expanded .. of .. Die Stebbing- 
Third maxilliped with ischium not expanded ¥F ‘ - 2. 
2, Female with exopods on at least first and second perseapoda. “Adult male (where spon) 
with terminal telsonic spines absent or similar to those of female 
Female with thoracic exopods completely absent. Adult male with terminal telsonic arian 
which are long and bristle- dike, much see in Sngth than the roaensny ones of 
female 7 oD 
3. First antenna unnsually ddswes ; the first siipliestt of ‘pedunele i is , dilated distally, while the 
second, which reaches beyond level of apex of pseudorostrum, is expanded proximally 
Sheardia gen, nov, 
Virst antenna, small or moderate, with the proximal] segments of podunels 2 not at all Gitaies, 
and the second not reaching to level of apex of peeudorostrum .. 

1) No. 11, The Family Diastylidae (part i) see Trans. Roy. Soc., 8. Aust., xix (2), 1945, 
pp. 173-211, fig, 1-26. 
