Boone, Crustacea, Cruises of "Ara" and "Alva" 269 



ately posterior to these four similar carinae but which are inter- 

 rupted by the deep cervical groove. On the postcervical region 

 (counted in the median line) there are normally twelve trans- 

 verse carinae, slightly interrupted by the cardio-intestinal grooves 

 in the center and separated from the sides, by the lateral line, 

 from similar carinae which are a continuation of the dorsal 

 carinae. Each of these carinae is a finely beaded line, margined 

 anteriorly by short, fine silky cilia. The first of the precervical 

 carinae bear the above-described preorbital and antennal spines. 

 The second carina bears in line with the preorbital a submedian 

 pair of spines, and on either side of these variously 2, 3, or 4 

 spinules, which on young specimens are very small, sometimes 

 obsolete. The third carina bears a submedian pair of spinules, 

 sometimes with also a median spinule and usually anotiier pair 

 of spinules, one each just above the hepatic sulcus. There are 

 also about four, sometimes five, spinules, along the anterolateral 

 margin of the precervical carapace and another spine on the first 

 postcervical carina near the margin. There is nearly always a 

 single spinule, larger than the average, situated in the median 

 lateral area, above and slightly posterior to the cervical groove. 

 There are also usually six, sometimes only four, spinules, three 

 each submedian along the inner portion of the first postcervical 

 carina and a single submarginal spinule. There normally are no 

 more spines or spinules on the dorsad of the carapace, but the 

 first postmarginal carina of the sidewall is continuously spinu- 

 lose with ten to twelve spinules; posterior to the last of these 

 and just below the sulcus there are three or four spinules, one 

 each on the third, fourth and fifth carinae, while above these yet 

 on the sidewall are about six larger spines, the first of which is 

 just below the lateral line and in continuation of the marginal 

 spines of the dorsad series of the carapace ; then there are four 

 lateral spines occurring one each on alternate carinae, the fourth 

 spine being in line with the second postcervical carina ; behind this 

 fourth spine and more dorsad are two more spinules, each on 

 alternate carinae, the sixth one being subdorsad, almost in line 

 with the first spinule of this series. 



The anterior margins of the first, second and third abdomi- 

 nal somites are each spinulose, there being four spines each on 

 the anterior margin of the first or most anterior carina of each 



