Ortmann — Linuparus atavus. 295 



exact number of the spines cannot be determined. Each 

 abdominal segment has a transverse furrow passing across the 

 back between the anterior and the posterior median spines ; 

 these furrows are very distinct on the second, third and fourth 

 segments, while they are obsolete on the first, fifth and sixth. 

 Of the telson only a small part of the anterior portion is 

 exposed ; the posterior end, which was probably — as usual in 

 this family — soft, is imbedded in the hard matrix. 



The segment of the antennulce is very like that of Palinurus 

 or Linuparus. It is narrow, elongate-triangular ; the lateral 

 borders form a blunt, elevated ridge. The episioma has a deep 

 median longitudinal furrow, which is bordered anteriorly by a 

 strongly elevated, oblong tubercle on both sides. The phyma- 

 cerite (opening of the green gland) is visible only on the left 

 side of specimen (a). The sternum, exposed beautifully in 

 specimen (b), is elongate-triangular in outline. The lateral 

 borders have three spiniform tubercles near the insertions of 

 the second, third and fourth pereiopods, and a similar median 

 tubercle a little in advance of the level of insertion of the fifth 

 pereiopods. 



Of the antennulce only parts of the basal joint are preserved. 

 The antennae show the stout and enlarged form usual in the 

 family. The stems have three free joints, the basal one being 

 greatly enlarged and dilated on the inner margin, thus form- 

 ing, with the segment of the antennulse, that peculiar u stimu- 

 lating apparatus " found in the genera of group 2 and 3 of the 

 family. The two other basal joints of the antennae are nar- 

 rower than the basal one, but still large and powerful. All 

 three joints are furnished with a number of smaller and larger 

 spines. Of the flagella only a couple of fragments are pre- 

 served, but these show a very peculiar feature only found, 

 among the living genera, in Linuparus: there exists dorsally 

 and ventrally a distinct longitudinal furrow, so as to render 

 the cross section oval with a constriction in the middle. 



Of the mouth parts, traces of the strong and powerful man- 

 dibles are seen in specimen (a), of the second maxillipeds in 

 specimen (£), and of the third maxillipeds in both. Of the 

 latter the distal joints, carpus, propodus, and dactylus, are 

 broken away. The interior margin of ischium and merus is 

 spiny. No traces of an exopodite have been discovered, but 

 it is probable that it is broken away or still imbedded in the 

 matrix. 



Of the pereiopods (thoracic legs) the first seems to be the 

 stoutest, the second the longest. In specimen (b) all the joints 

 of the latter are preserved on the right side (but partly cov- 

 ered by the matrix). The dactylus reaches as far as the end 

 of the stalks of the antennae, and it is long and slender. The 

 dactylus of the first periopods is nowhere visible, but in both 

 specimens the propodus of the left sides, showing plainly that 



