52 



(PI. V, figs. 2g—2i, ch.) and much of it scabrous from numerous small, sharp knots; besides 

 it is slender with the end distinctly expanded and oblique. In L. infertnediits the well chitinized 

 part of the sheath has its end broadly rounded, and somewhat before the end on the side 

 opposite the base of the petasma two plate-shaped, rather conspicuous protuberances (/. in 

 PI. V, figs. \e, if, ig), and on the distal part of inner surface a number of nearly regular, 

 transverse, very fine but conspicuous lines {s. in fig. if). In L. typus and L. orientalis the 

 terminal part of the petasma is considerably thicker than in the four other species; in L. typus 

 (PI. IV, figs. 6g — 6 k) its rather broad end is obtuse with a nearly rudimentary, triangular 

 protuberance; in L. orientalis (PI. IV, figs, "je — 7/) the end is broad and divided into three 

 triangular lobes; in both species nearly more than the distal third of the inner surface is adorned 

 with transverse, conspicuous lines [s^. In L. typus the sheath encloses not only the above-named 

 plate-shaped processus ventralis, but besides a long, well chitinized, stick-shaped process (PI. IV, 

 figs. 6// and 6k, h.), which has its distal part strongly bent so that the process is a hook with 

 a long shaft and the end very acute; I am unable to interpret the morphological equivalence 

 of this hook which does not e.xist in the five other species. The figures and the explanation of the 

 plates will add various particulars and help to the understanding of the brief description given. 



In all species a protuberance is observed on the front margin of the first male pleopod 

 slightly beyond the petasma. The shape of this protuberance (/. in PI. IV, figs. 6g and 7^, 

 PI. V, figs, le, 2g^ T,g, 4/, 4m) and its equipment with prickles on the end is not without 

 specific value. 



The 6 species may be divided into two groups, separated by some characters. 



A. Distance between the labrum and the insertion of the eye-stalks somewhat or only a little 

 longer than the eye-stalks with eyes (the basal short joint of the stalks included). Posterior 

 ventral process on si.xth abdominal segment in the male with its distal part swollen. Terminal 

 portion of the petasma moderately thick, and the processus ventralis .shaped as a somewhat 

 broad plate without any terminal brush. 



B. Distance between the labrum and the insertion of the eye-stalks almost twice or more than 

 twice as long as the eye-stalks with eyes. Posterior ventral process on sixth abdominal 

 segment tapers to the narrow, obtuse end. Terminal portion of the petasma rather or very 

 slender, and the processus ventralis never shaped as a somewhat broad plate without brush, 

 but either slender or terminating in a bipartite brush. 



Group A. 



The animals of this section differ in aspect very considerably from those of group B by 

 the long eye-stalks. These stalks have besides their major part very slender; the eyes are 

 conspicuously larger than in group B, and larger in the males than in the females. The exopod 

 of the uropods is very narrow, in the males from more than five to six times as long as broad, 

 in the females from five to somewhat more than five times as long as broad. 



The group comprises only 2 species. While I have been unable to find any sufficiently 

 sharp difference between the females of these species, their males are extremely easy to separate 

 by the following key. 



