88 Bulletin Vanderbilt Marine Museum, Vol. VI 



Technical description : The rostral carina extends almost 

 to the postlateral margin of the carapace and is lightly channelled 

 from its origin to the base of the epigastric tooth. The rostrum is 

 nearly straight and the acute apex extends as far as does the 

 antennular peduncle ; the lateral rostral carina arises in advance 

 of the epigastric tooth and is less distinct than is that of Peneu^ 

 indicus. The epigastric tooth is three-fifths of the carapace 

 length from the posterior margin, and is one and one-half times 

 as far from the second tooth, which is approximately in line with 

 the hepatic spine, as the second tooth is from the third tooth ; the 

 second to seventh teeth, inclusive, are almost subequally spaced, 

 the distal upper tooth being a little in advance of the first tooth of 

 the lower margin, which is in line with the distal corneal margin ; 

 the three teeth of the lower margin are rather closely, subequally 

 spaced, the distal one being not far from the rostral tip. The an- 

 tennal spine is an acute-tipped fold of the carapace, which forms 

 the short, slightly oblique antennal ridge that vanishes below the 

 hepatic spine. The hepatic spine is normal, the cervical ridge 

 above is weak and faint, vanishing less than half-way to the dorsal 

 line. The hepatic sulcus is deep, tomentose beneath the hepatic 

 spine and defined below by a short, almost horizontal ridge, which 

 vanishes abruptly some distance behind the antennal border. In 

 Peneiis monodon this ridge is oblique, thus differing from that of 

 P. semisulcatus. The upper border of the hepatic sulcus of P. semi- 

 stdcatus is defined along its posterior two-fifths by a short ridge 

 which is posteriorly contiguous with the upper side of the faint 

 cervical groove and anteriorly vanishes one and one-half times its 

 length from the frontal border. 



The abdomen is carinated on the posterior three-fifths of its 

 fourth segment and on the entire fifth and sixth segments, this 

 carina terminating on the sixth segment in a small spine. The 

 telson is equal in length to the sixth segment and has a weak 

 median longitudinal groove on the proximal four-fifths. The 

 uropoda are typically Peneus. 



The eye has the stalk well developed, calcareous, with several 

 nodes and depressions on the upper surface; the cornea is set 

 obliquely terminal, and appears reniform in a dorsal view, but 

 nearly spherical from the lower side. 



The antennulae have the peduncular articles heavily tomentose 



