﻿CRUSTACKA M.\LAC( >STRAC.\. II. 



iinniatnre specimens of l)otli sexes ])roves that adult males must be either vcrv rare or, and 

 much more probably, that the\- swim about aud are therefore rarely taken with the trawl or the 

 dredoje. 



Immature or subadult males of many species were taken together with the females. In all species 

 with the pleopods quite rudimentary or wanting in full-grown females with or without marsupiuni 

 such subadult males are instantly recognized by having uuiderately developed or even somewhat lar"-e 

 pleopods; this is the case in several species of l.cploi^imlliin, in Pscudotaiiais forcipatiis and /-'. l.illjc- 

 borgii. in Agathntaiuiis. Lcpti\iiii(ithiillii. Stiuiiioyiiira, PurdiKnihriira. In all these forms the subadult 

 males have the abdomen proportionateh' either a little or. as in I'anniartlinira insigiiis n. sp., consid- 

 erably longer than the female. In the genera with the autennuke four-jointed the.se appendage.s, and 

 especiall}" their two proximal joints, are generally conspicuouslx' thicker in the subadult males than in 

 the females, and in some species of Lrplogiiafliid (f. instance L. itriiiata n. sj).) the antennuhe of the 

 subadult male are five-jointed, as the fourth joint has its basal part marked off by an articulation. 

 In species of Psciicfofai/nis or [.cpfogiialhiii with the pleopods well developed in the female and in all 

 species of Typ/ilofaiiais the autennuke alone afford readih- distinguishable differences between females 

 without marsupiuni and subadult males. In Typldnfaiiais the main difference is the thickne.ss of the 

 two proximal joints and of a ]3ortion of the third joint; in Psnidofauai.s we find generally the basal 

 part of the third antenuular joint somewhat thickened and besides protruding below. 



It is a common rule that when a good material of full-grown females of a species is to hand, 

 the great majority are without marsupiuni, even when taken at the same station. But it is a curious 

 fact that in se\eral cases some of the largest specimens without marsupiuni are a little longer than 

 the longest .specimen with marsu|>iiiiu; this fact I cannot explain, but I am induced to think that 

 some reduction in size may accoinpaii\- the development of the inarsupium and the eggs. In females 

 with marsupiuni the \-entral surface of the lamelligerous or of all thoracic segments is rather or quite 

 flat, in specimens without marsupiuni most frequently considerably convex, but specimens without 

 marsupiuni are sometimes found showing the ventral surface flat and on the whole showing an 

 appearance as if the marsupial lamellae had been lost, but whether this has been the case is imposs- 

 ible to decide. 



In females without marsupiuni and subadult males of se\'eral species of 'I'xphlotaiiais and of 

 Lrpt<ig)i(ifhia vciitraUs n. sp. the second thoracic segment is below, and generall>- at or not \-erv far 

 from the front ventral margin, ])roduced in a generally acute and sometimes large process directed 

 downwards and more or less forwards; in females with marsupiuni and in \-er\- few cases in female 

 specimens without marsupiuin (perhaps lost) but with the lower side of the thoracic .segments nearly 

 or (]uite flat this process is either reduced in size and slia])e ( LtptogiKiHiia vciifralisi ok lost (Tyfi/ilo- 

 tiniais). — In Typhlotaiiais iiiicroc/if/rs tx. ( ). .Sars females without marsupiuni and with the ventral 

 side of the thoracic segments convex, the \entral process is found on all thoracic segments excepting on 

 the seventh (vid. "Remarks" on 7. gnirilipts u. sp.) — In Paniiiarfltrura iiisigiiix n. gen., n. sp., the 

 females without iiiarsu])ium and subadult males lia\e a conspicuous j)rocess on the \enlral side of all 

 thoracic segments, but in females with iiiarMijiium onl\ the process on the sexeiith segment has 

 been preser\'ed. 



