67 



Remarks. This new family at present comprises only a single genus, 

 which, however, cannot properly be placed in any of the other families here 

 recorded. In some features, and more especially in the structure of the anterior 

 maxillipeds, it exhibits some resemblance to the Phaennidce; but the uniform 

 appearance of both the anterior antennae and the oral parts in the two sexes 

 proves it in reality not to belong even to the same section, but evidently to the 

 one here in question, viz., the Iso/cerandria, 



Gen. 18. TharybiS 1 ), G. 0. Sars, n. 



(lemric Characters. Body unusually short, with the anterior division 

 considerably tumefied. Front without any rostral prominence. Urosome rather 

 short in female, considerably more slender in male. Caudal rami short, each with 

 3 apical setae. Eye of a somewhat unusual appearance, being very large and 

 placed close to the dorsal face. Anterior antenna? 24-articulate, with scattered 

 bristles in front, last 2 articulations well defined. Posterior antennas with the 

 inner ramus rather small. Mandibles strorg, with the masticatory part very com- 

 pact, cutting edge exhibiting outside 2 unusually strong bifid teeth followed by a 

 dense series of partly ciliated setae, palp with both rarai well developed. Maxillae 

 of a somewhat unusual appearance, the masticatory lobe being exceedingly large, 

 with strong spines inside, whereas the palp is comparatively poorly developed. 

 Anterior maxillipeds with the terminal appendages extremely delicate and penicillate 

 at the tip, as in the Phaennidce. Posterior maxillipeds not much elongated, 2nd 

 basal joint fusiform, terminal part comparatively short and not reflexed. Natatory 

 legs of moderate size, and without any spinules on the hind face. Last pair of 

 legs in female 3-articulate, terminal joint linear and strongly spinous at the tip; 

 in male very large and rather asymmetrical, left leg biramous, right simple. 



Remarks. Dr. Giesbrecht would probably have placed this genus within 

 his sub-family Scolecithrieince, which also comprises the genera Xanthocalanus 

 and Phaenna; and indeed/ in external appearance, and more especially in the 

 structure of the anterior maxillipeds, it strongly recalls the last-mentioned genus. 

 It is, however, in reality very different, being not only distinguished by the uni- 

 form appearance in the two sexes of both the anterior antennae and the oral parts, 

 but also by the presence in the female of distinctly developed legs of the 5th pair. 

 We know at present only a single species, to be described below. 



l ) Nomen proprium. 



