SCHIZOPODA. 
27 
therefore, the fourth and fifth pleopods will likewise be found to be biarticulate when 
perfect specimens are examined. In H. antarctica only the fifth pleopods are 
biarticulate, the remaining pairs consisting of a single joint only. 
The eyes in the genus are described for the first time. They are remarkable 
chiefly for their small size and degenerate structure, for the complete absence of visual 
elements, and the subservience, either entirely or in great part, of ophthalmic functions 
to those of probably a tactile nature. 
The cap-like form of the tergum of the first segment of the pleon recalls the 
somewhat similar form of the third pleon segment in many Carida, and suggests that 
the posterior part of the body is capable of great ventral flexure. The ‘ Discovery ’ 
expedition is to be congratulated on the finding of this species, by far the most 
interesting Schizopod in the collection. 
Family MYSIDflE. 
Sub-Family Leptomysiisle, Norman. 
Genus Pseudomma, G. 0. Sars. 
PSEUDOMMA BELGICAt 
(Plate VI., Figs. 1-8.) 
Pseudomma lelgicae, Holt and Tattersall, 1906 (1). 
Locality of capture. —Lat. 78° 25' 40" S., long. 185° 39' 6" E., 300 fathoms, one 
specimen, immature female, 23 mm. 
Form (Fig/1) compact and moderately stoutly built. 
Carapace (Fig. 1) large, less than half the total length of the body, covering 
laterally all the segments of the thorax, but clorsally exposing the last one behind its 
posterior emargination ; its anterior margin very slightly produced into a blunt, very 
broadly rounded rostrum ; antero-lateral angles rounded; cervical sulcus well marked. 
Pleon (Fig. l), excluding the telson, about half the total length of the body from 
the eye to the tip of the telson ; first four segments subequal in length and slightly 
longer than the fifth ; sixth segment twice as long as the fifth. 
Eye plates (Fig. 1) contiguous, exhibiting only a very slight anterior median 
cleft; each plate subquadrangular or rliomboidal in shape, nearly twice as broad as 
long, antero-lateral angles rounded, anterior margin nearly straight, no serrations or 
armature of any kind; no pigment present in preserved specimens ; corneal lenses 
absent, but the ramifications of the optic nerve are clearly visible in dorsal view. 
Antennular peduncle (Fig. l) short and stout, not extending beyond half the 
length of the antennal scale ; basal joint almost entirely covered by the ocular laminae, 
a few plumose setae on each anterior corner; second joint very short, more than twice 
as broad as long, a few short setae on the outer distal corner, inner margin with a few 
longer plumose setae ; third joint longer than either of the other two and slightly 
/fo&.cj 2Z . /SB" 
