Plate 1 issued from : E. Suarez-Morales & E. Islas-Landeros in Hydrobiologia, 1993, 271. [p.47, Fig.1].
Female (from off Puerto Morelos, Yucatan): a, h, , habitus (dorsal and lateral, respectively); b, A1 (dorsal); c, P1; d, P2; i, P3; j, P4; e, genital complex (ventral); f, urosome (lateral; another specimen); g, urosome and caual rami (dorsal); k, detail of oral papilla (lateral).

Nota: Cephalothorax 60 % of total body length. Oral papilla prominent, cylindrical, with small associated prominent; papilla located 42 % of way back along ventral midline of cephalic somite. Eye present, ocelli poorly developed. Cephalothorax reticulated. A1 with one articulation in proximal segment; each A1 with 4 constrictions which appear as sutures (appearing as 5-segmented). P5 fused medially, each leg with 2 distinct lobes, innerlobe (endopodal) without armature, outer lobe (exopodal) bearing 2 subequal terminal setae, each with setulae distribued along its length. Urosome consisting of 5th pedigerous, genital double-somite and 2 free somites; ratio length of genital double-somite and two free somites 62.8:17.2:20.0 = 100. Genital double-somite bearing 2 short ovigerous spiniform processes on ventral surface; spiniform process about 6 % of total body length. Caudal rami about 1.9 times longer than wide, moderately divergent, bearing 4 setae, one lateral and 3 terminal.
The armature of the swimming legs is nearly the same in both species M. wandelii and M. mariaeugeniaze, but in the latter lacking an external seta on the basis of the 3rd and 4th legs (present in M. wandelii. In both species A1 show only one proximal articulation, but the 5 constrictions described for M. mariaeugeniae are not present in M. wandelii, whose A1 show a more slender and homogeneous shape. The proportional length of the A1 and the cephalic somite also differs in both species; moreover, in M. wandelii, the armature of A1 includes 3 terminal long setae on the distal portion of the last segment; in M. mariaeugeniae the A1 show no distal armature.

Plate 2 issued from : E. Suarez-Morales & E. Islas-Landeros in Hydrobiologia, 1993, 271. [p.46
Female: Formula for armature of swimming legs.

Plate 3 issued from : E. Suarez-Morales in Crustaceana, 1996, 69 (1). [p.36, Fig.1]. As Monstrilla wandelii tropica.
Male (from off Puerto Morelos, Yucatan): A-B, habitus (dorsal and lateral, respectively).
Nota: Cephalic somite plus incorporated 1st pedigerous somite almost 0.60 of total body length. Oral papilla prominent, located at 0.40 along the ventral surface of gephalothorax. Ratio of length of genital and free somites 33.6:28.7:13.3:13.4:10.89 = 100.

Plate 4 issued from : E. Suarez-Morales in Crustaceana, 1996, 69 (1). [p.37, Fig.2]. As Monstrilla wandelii tropica.
Male: A-B, A1 (dorsal and ventral, respectively); C, 5th pedigerous segment with P5, and genital apparatus (ventral).
Nota: A1 0.38 of total body length, both antennulae geniculate, 5-segmented, segments 2-4 partially fused, with articulation between segments 4 and 5, 5th segment with terminal chela; length ratio ao antennular segments 11.1:16.6:23.6:23.7:25 = 100.

Plate 5 issued from : E. Suarez-Morales in Crustaceana, 1996, 69 (1). [p.38, Fig.3]. As Monstrilla wandelii tropica.
Male: A, genital apparatus (lateral); B, caudal rami (dorsal).
Nota: Genital segment with a prominent genital protuberance, with a pair of genital lappets which have a bolobular structure; inner lobe rounded, with small setae on surface; outer lobe broad at base and sharpening toward its distal end. Genital apparatus 0.65 of total urosomal length. Caudal rami about 0.7 times longer than wide, bearing 1 long lateral seta and 2 well developed and 1 small terminal setae.

Plate 6 issued from : E. Suarez-Morales in Crustaceana, 1996, 69 (1). [p.36, Fig.1]. As Monstrilla wandelii wandelii Stephensen, 1913..
Male: Armament formula of the swimming legs.