MOKPHOLOGICAL METHOD AND RECENT PROGRESS IN ZOOLOGY. 597 



has also provided a report which eiiihnices the description of a 

 nauplius of exceptioimL type, which, by a process of reasoning- ))y 

 elimination, masterly in- its niethod, has been ''run to ground ■" as in 

 every degree of probability the larva of Darwin's apodal barnacle 

 Protolejxm hivlncta^ of which only the original specimen is known. 



There is but one other crustacean record equal in rank with this, 

 viz, the discovery of the genus Ana.'ipidex. Originally ol)tained from 

 a fresh-water pool on Mount Wellington, Tasmania, at 4,000 feet, it 

 has since l)een found in two other localities. It is uni([ue among all 

 living forms, in com])ining within itself characters of at least three 

 distinct suborders of "prawns," for Avith a schizopod body it com- 

 bines the double epipodial lamella of an amphipod, th(^ liead of a 

 decapod (pedunculated eyes and antennulary statocysts) apart from 

 characters peculiarly its own. There is reason to I)elieA'e that the 

 nearest living ally to this remarkable creature is a small eyeless species 

 {BatJiyneUa natana) obtained from a Bohemian well; and if its pre- 

 sumed relationships to the Paheozoic '"pod-shrimps'' I )e correct, this 

 heterogeneous assemblage may perhaps l)e the rei)resentatives of a 

 group of primitive Malacostraca, through which, ])y structural diverg- 

 ence, the establishment of the higher crustacean sul)orders may have 

 come about. 



It is pertinent to this to note that work upon cave dwelling and 

 terrestrial forms, upon "well shrimps"'' and the like, has produced 

 important results. And interesting indeed is the recent discovery of 

 three species, living at 8(><) to 900 feet above sea level, in Gippsland, 

 one an amphipod, two of them isopods, which, though surface dwell- 

 ers, are all ])lind. While they prove to be species of genera normally 

 eyed, they in their characters agree with well-known American forms; 

 and the bleaching of their bodies and atrophy of their eyes proclaim 

 them the descendants of cave-dwelling or subtei'ranean ancestors, 

 among whom the atrophy took place. 



Iluxlev in ISSO rationalized our treatment of thi^ higlun' C'rustacea, 

 by devising a classitication l)y gills, expressive of the relati()nsliii)s of 

 these to the limb-bases, interarticular meml)ranes, and body wall. 

 Hardly had his influence taken eft'ect when, by work extending over 

 the years 18S(; to 18!>3, in the study of Pena'us, the riiyllopods, 

 Ostracods, and other forms, evidence had Ixmmi accunndating to show 

 that the crustacean appendag(% even to the mandible Itself, has prima- 

 rily a basal constituent (protopodite) of three s(\gments: that the 

 l)ranchiie one and all are originally ai)pendicular in origin; and that 

 the numerical reduction of the basal (protopoditic) segments to two, 

 with the assumption of a nonappendicular relationship ])y the gills, 

 is due to coalescence of parts, wdth or without suppression. The e\i- 

 dence for this (^poch-making conclusion, which simplifies our conc(^p- 

 tions and brings contradictory data into line, is as ii-re.sistihie as it is 

 important, and there has been nothing finer in the whole history of 



