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Show 958 DR. H. J. HANSEN ON CRUSTACEANS [Dec. 1, times shorter and very narrow; the first branchia above trl.4 is half as large as the corresponding one above trl.3, the second half as large as the first but a little larger than the second above trl.3. (In somewhat younger specimens with yellowish eyes all 4 branchiae are very distinct; the animals are, for the rest, relatively shorter and stouter.) The ext. br. of urp. without any spine on the exterior margin, of which the ciliated part occupies from a little more than the half to about three-fifths of the length. As to the half-grown larvae, the representations of Kroyer and Bate will be sufficient.-A younger larva, 6*4 m m . long, coincides fairly well with 8. utrlnquedens, Bate (p. 433), in most respects, but yet differs in several particulars from Bate's description. The supraocular and hepatic spines are well developed; the rostrum is almost as long as the eye-stalks (the eyes not included), with a short and fine dorsal spine at the base; the eyes are much larger and the eye-stalks longer than in the stage described by Kroyer and Bate. The third joint of the antenn. ped. is but a little longer than the second, and the first one as long as the two others taken together. The fourth to sixth abdominal segments each with a very short and fine dorsal spine, the epimera of the first to fourth segments each produced into a short spine, while this spine is considerably longer on the epimera of the fifth segment; the first segment besides on the side having a spine arising from the anterior margin and directed forwards and outwards. On the ext. br. of urp., which is almost seven times longer than broad, the ciliated part occupies a little more than the half of the exterior margin, wdiich-as in almost all young larvae-is furnished with a well-developed spine. Of 8. corniculum, Kr., I have seen numerous specimens from the Atlantic northward to lat. 42° N., from the Indian Ocean and ranging into the Pacific to the Matelota Island and to lat. 16° 10' N., long. 132° E. Whether the above-quoted S. utrlnquedens, Bate, may be a young larva of S. corniculum, Kr., or of another species I am not able to decide. S. longlrostrls, Bate (p. 415, pl. lxxv. fig. 3).-Prof. C. Chun has determined the small stage of S. corniculum, Kr., just described as S. longlrostrls, Bate, which is stated to be 6 m m . long and captured in " Mid Atlantic," and it is very possible that this determination may be correct; but Bate's figure represents the eye-stalks and the rostrum a little too long, and especially a different proportion between the joints of the antenn. ped. &c. I believe that it is impossible to decide whether this identification is correct. Above I have further enumerated 5 species belonging to Group I. Of these species S. prcecollus, Bate (p. 423, pl. lxxvii. fig. 2), is at least rather nearly related to S. corniculum, Kr., from which it seems to differ by a somewhat different shape of the ext. br. of urp. and by having the fifth abdominal segment " dorsally produced to a point." 8. longlcaudatus, Stimps. (p. 46), is a larva perhaps belonging to the arctlcus-grouy. On the three other species, all larvae, I have no opinion. |