560 TAGE SKOGSliEP>G 



Seventh limb: — This shows no dimorphism and varies very sHghtlv in this group. 

 It seems to serve chiefly as a sort of cleaning organ, but its effectiveness does not seem to be 

 very great; cf. G. W. Muller, 1894, p. 73; it is probably to be taken as a very much reduced 

 organ. Like the cleaning limb in the Cypridiniformes it is placed fairly high up on the side 

 of the body, somewhat behind the sixth limb. Wlien in a position of rest it points in most cases 

 obliquely upwards and backwards. It is very small and consists of quite a short, two-jointed 

 or unjointed stem, which grows somewhat narrower distally and is furnished with simple, 

 moderately strong musculature. (The question of the morphological value of this stem seems 

 at present impossible to decide with certainty; does it correspond to the protopodite + the 

 exopodite or only to the exopodite? See p. 50 above. The latter alternative seems most prob- 

 able to me.) The e p i p o d i a 1 appendage and the endopodite are quite absent. 

 The proximal joint, which is somewhat elongated, is quite without bristles. The end joint is 

 short and has two well-developed distal* bristles. 



The b r u s h - s h a p e d o r g a n is quite absent. 



Fur c a: — This is always well developed, rather large and powerful with short, broad 

 lamelliform rami, armed with a varying number of claws: from two to eight were observed. 



The heart is always developed? 



Sensory o r g a n s — Quite blind forms** ; no traces of either lateral eyes or a Nauplius eye, 

 have hitherto been found. (G. 0. Sars pointed out in his work of 1865, pp. 116 — 117, the following 

 facts: ,,In basi vero antennarum superiorum corpuscula adsunt pluria lentiformia, irregulariter 

 acervatis sed semper in stratu distincte nervoso collocata pigmento vero nullo circumdata, 

 quae organa quamquam imperfecta visus esse videntur." In this writer's work of 1887, p. 70, 

 too, the occurrence of similar bodies is pointed out ,,en Del eiendommelige lindseagtige Legemer, 

 der maaske tor ansees for et Slags ufuldkomne Synsapparater"*** in the proximal part of the 

 first antenna in a couple of the Scandinavian species of the genus Conchoecia. This observation 

 is repeated by G. S. Brady and A. M. NORMAN, 1896, p. 685; they point out that the first joint 

 of the first ajitenna in ConcJioecia elegans G. 0. Sars ,, shows, irregularly scattered near its surface, 

 a number of lenticular bodies overlaying patches of red pigment, perhaps rudimentary visual 

 organs". I have found similar patches in the first antennae not only of C. elegans and C. horealis, 

 the specL'S referred to by G. 0. Sars, but of a great number of species of this genus; in exceptional 

 cases these are also found in other places, e. g. on the protopodite of the second antenna in, for 

 instance, G. hettacra G. W. Muller. It seems very uncertain whether these bodies are visual 

 organs but it seems best not to make any statement as to their morphological value before 

 any experiments at all have been carried out. In any case such statements could only be very 

 uncertain.) 



A r o d - s h a p e d organf is developed in most cases. 



»» 



Only ill exceptional cases, in single specimens, are three Ijristles fouml. 

 F(rr .r. n. Dana's establishing of eyes (1852, p. 1297) see p. 562 below. 

 *** ,,Sonie peculiar lenticular boilies, which are perhaps to be interpreted as a sort of imperfect visual organs." 

 t G. VV. Mii.i.ER (iroposes (I8i)'j, p. 168) as the ..walu'scheinlichste, oder, wenn man vWll, am wenigsten 

 n iw.ihrscheinliche" explanation of the rod-shaped organ in the II a I o c y p r i il s that il is a light-percipient organ, 

 not, howi;vcr, fui' forming images, but only for .,cine Unlerscheidung vmi hell und dunlicl". 



