Antennae. First: (Female). Peduncle, last 2 segments ½ length 1st. Flagellum curved, inner margin has projections and setae as in P. gracilipes; the one segment more than twice peduncle length; distal portion finely bristled all over. Second: (Female). Peduncle, last 3 segments ¾ flagellum length; 3rd segment ½ length 5th, slightly shorter than 4th, all finely bristled.
Gnathopods. First: (Male.) Propod slightly curved, width ⅖ length; 3 spines and comb on posterior margin, 6 long spines on anterior, about 6 on anterodistal surface. Curved dactylos ½ propod length, inner margin finely toothed. (Female.) Basos width ⅓ length, a few setae on surface, tuft of stout spines on posterodistal angle. Ischium wider than long, ¼ basos length, strong rank of spines on posterodistal angle. Merus subrectangular, width nearly ⅔ length, free distal margin with rank of very long spines. Carpus oblong-ovate, width ½ length; anterior margin, median surface and posterior margin very strongly spined. Propod
Text. Fig 11.—Parathemisto australis (Stebbing). 177—Head of female. Parathemisto gracilipes (Norman). 178—Head of male. Parathemisto australis (Stebbing). 179—Peraeopod 1, ♂. 180—Peraeopod 1, ♀ carpus. 181—Peraeopod 2, ♂. 182—Peraeopod 2. ♀, carpus. 183—Peraeopod 3. ♂. 184—Peraeopod 5. ♂. 185—Uropods and telson. 186—Uropod 3 peduncle inner distal angle. 187—Uropod 3. inner margin of inner ramus. Phronima sedentaria. (Forsk.) Female 188—Antenna 1.189–Maxilla 1.190—Maxilla 1. outer plate. 191—Upper lip. 192—Maxilla 2. 193—Mandible. 194—Maxilliped.
barely shorter, width ⅖ length, slightly convex, anterior margin and surface strongly spined; posterior margin with a few strong spines, finely toothed; dactylos ½ propod length, inner margin finely toothed proximally. Second:. Basos width ¼ length, strong spines at posterodistal angle. Ischium ⅕ basos, strong spines on posterodistal angle, wider than long. Merus ovately spoon-shaped, ⅖ basos length, and reaching nearly ½ along carpus, process as long as merus proper, its margins strongly spined. Carpus proper ½ basos length, process extending ¾ along propod, anterior margins of carpus and propod strongly spined; carpus posterior margin free, process inner margins strongly spined, several spines at process end. Propod as long as carpus proper, a few setae on finely toothed posterior margin. Dactylos inner margin proximally toothed, length ½ propod.
Peraeopods. First: (Male.) Merus less than ½ carpus length, about 3 fine spines on posterior margin, as wide distally as long. Carpus margins strongly convex, widest a little before midpoint, width ½ length, a few fine setae anteriorly, fine spines on posterior surface and margin, comb of fine teeth on posterior margin. Propod as long as carpus, width about ⅕ length, about 8 small spines on surface, posterior margin finely toothed, dactylos ½ propod length. (Female.) Propod slightly more than ½ carpus, carpus widest proximally, fine bristles on carpus and propod surfaces. Dactylos not ½ propod length, carpus width more than ½ length.Second: (Male.) Not greatly different from Pr. 1, male. (Female). Like male, carpus width ½ length, propod as long as carpus.
Urosome. Outer rami inner margins and inner rami outer margins finely toothed. Uropod 2 has these margins excavate and proximally bristled; peduncle and inner margin of uropod 3 inner ramus, smooth. First: Peduncle, inner ramus and outer ramus in ratio 5:4:3. Second: Ratio 3:3:2 Third: Ratio approximately 4:3:2 Telson reaching about ¼ along peduncle of uropod 3.
The dorsum is strongly spined in specimens from about 12 mm. upwards. In P. gracilipes, specimens of 9 mm. and 11 mm. show very slight signs of dorsal spination.
Hypotypes. Slides L.6, male; L.7, female.
The largest specimen, 18.3 mm., was a female.
Distribution. Southern Atlantic (35°-68° S.); Northern Atlantic (40°-76° N.); Australasian region (48°–63° S.); Southern Indian Ocean (40°–50° S.).