956 DU. H. .T. IIANS15N ox CnUSTACBANS [Dee. 1 , 



reach to the middle of the second joint of the auteun. ped. ; the 

 basal joint of this peduncle is to the two following together as 11 

 to 8 ; trl.* and trl.' are only buds. The first and second abdominal 

 segments each witli a short dorsal spine, the third to sixth segments 

 each with a long spine ; the first segment a little above the middle 

 of each side with a rather short spine directed outwards, and 

 besides the epimera of the five anterior segments each produced 

 into a rather long spine, which is directed outwards and on the 

 two anterior segments even bent somewhat upwards and forwards ; 

 the sixth segment below on the posterior edge with a shorter 

 spine. The ext. br. of urp. is about 8 times longer than broad, 

 and the spine a little beyond the middle of its exterior margin. 

 Telson with a long process from each of its posterior edges. 



The following stage is that described by Krciyer : the rostrum is 

 as already mentioned, the hepatic spine has become somewhat 

 shorter than in the preceding stage ; on the abdomen the dorsal 

 spines are somewhat reduced and tlie epimeral spines are lost, but 

 the spine on the side of the first segment is still visible. 



During the subsequent stages a series of alterations take place. 

 The rostrum becomes shortened, but is, however, still during a 

 longer period more than half as long as the eye-stalks, its dorsal 

 spine and the hepatic spines are considerably shortened, the eye- 

 stalks become somewhat shorter ; the median protuberance is pre- 

 served during some time; the abdominal spines soon completely 

 disappear. In the antenn. ped. the two distal joints together 

 successively are approaching the length of the basal joint, which 

 from being distally slender with the lateral margins slightly con- 

 verging obtains a considerable breadth with the external margin 

 somewhat convex in outline. The ext. br. of urp. becomes pro- 

 portionally broader and the spine more remote from the middle 

 of the exterior margin ; the process from the edge of the telson 

 becomes shorter and finally disappears. One of these stages is 

 S. dissimilis. Bate, described by Bato (p. 437), and later on described 

 and figured by Ortmann (p. 35, Taf. iii. fig. 2). 



The sub-adult stage of S. medlterraneus, m., is shortly described 

 above. The smallest larva of this species known to me is about 

 9-5 mm. long, and this and a specimen a little longer are easily 

 distinguished from the similar stage of S. arcticus, Kr. The eye- 

 stalks are somewhat shorter ; the rostrum is rather short, not half 

 the length or about one-third of tlie length of the eye-stalks, with 

 a trace of a spine on its superior margin, the hepatic spine is rudi- 

 mentary or wanting ; in the antenn. ped. the two distal joints 

 together are shorter than the basal one, and this presents a shape 

 other than in S. arcticus, as in its distal half the lateral margins are 

 parallel with each other; and this part is scarcely broader than the 

 two distal joints, which are obviously coarser than in S. arcticus ; a 

 very short dorsal spine is present on the fourth to sixth abdominal 

 segments ; the ext. br. of urp. is proportionally broader than in 

 S. arcticus, between 4 and 5, but not 5 times longer than broad. 



As stated above, S. arcticus, Kr., has not been captured outside 



