30 



antennae shorter than the inferior, accessory appendage well developed, with 

 the 1st joint laminar. Oral parts greatly projecting inferiorly and crowded 

 togetlier in tlie form of a trifid tul3e. Ejiistome not projecting. Anterior lip 

 very elongated and narrow; ])ostprior lip witli tlie lobes acntely lanceolate. 

 Mandibles with the masticatory ])art styliform prodirced, cutting edge very 

 narrow, shai'pened and obliquely truncated, molar expansion (|nitp wanting, 

 accessory lobe inconspicuoiis, palp very large and densely setous. First pair 

 of maxillae with the masticatory lobe very narrow and di^'ided at the tip 

 into .small claw-like teeth, basal lobe small, unarmed, palp very minute, but 

 distinctly l)iarticulate. Second pair of maxillae with both lobes very 

 naiTow, styliform. Maxillipeds rather large, masticatory loljes linguifonn, 

 projecting infeiiorlj- and partly encompassing the other oral paits at the sides, 

 basal lobes verv narrow, iTuarmed, palp geniculate on the middle, with the 

 terminal joint lanceolate. Anterior gnathii]in(l:i enormously developed, prehensilp, 

 terminating with a very large subchelate hand, which in the adult aninml 

 becomes inverted in such maunei', that the dactylus oi'iginates from the infero- 

 posterior corner of the propodos and is bent forwards against the strongly 

 denticulated palm. Posteriiu- gnathopoda ((uite of the structiire typical to 

 the Lysianassida:'. Pereiopoda not very large, the joints more or less crnnpressed 

 and only beset with very minute and scattered spines. Branchial lamellae 

 very large and of irregular form. Incubatory lamellae rather broad and 

 fringed with numerous slender setae. Pleopoda very powerful. Uropoda with 

 the rami broadly lanceolate and almost bare, last pair with the outer ramus 

 biarticulate. Telson small, entire. 



lUiiKirls. — In classing this remarkable form, I have seen fit to dissent 

 wiih'ly from the views supported by earlier authors. Boeck regards this ani- 

 mal as the type of a distinct family (Prostomatae), which he place^ at the 

 head of his division Gnmniorina, immediately before the Orche.tfiidrr, and 

 Dr. r>o\allius has classed it, together A\-itli the genera Spiopia Dana and 

 Hypcriopsis Gr. 0. Sars, within a distinct tribe, Sijnopidea, constituting, however, 

 within the latter, a particular family, Trhchhontomatidce. Finally Prof. Lillje- 

 borg considers it the type of a subfamily, Trii/ckisoatomafina, placing it in the 

 vicinity of his sub-family Phoxina. Although Boeck has mentioned some points 

 of agreement with the Lyssianassidoe, none of these authors would seem 

 to have recognised the near relationship, which in fact exists between this 

 animal and the true Lj-.sianas.sidae. The agreement is indeed so very close, 

 that the present form, in my judgement, unquestionably ought to be classed 

 within the very same family. The oral parts have not yet been exactly 

 examined in their details, neither by Boeck, nor )jy Dr. Bovallius. Though 

 at first sight vri'\- anomalous, Ihcy arc rouiHl. im a closer examination to be 



