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SCIENCE 



[N. S. Vol. XXXIV. No. 875 



species typically have a variegated coloration 

 vfticli consists of bars, blotches, lines and 

 mottlings of white, slate, brown and black, the 

 predominating colors of the fishes of northern 

 regions. 



The coloration of the deeper-water species 

 is slightly modified by the environment. The 

 variegated coloration is retained, but in addi- 

 tion to this, in two or three species, a reddish 

 lining to the dermis and a silvery or a black 

 peritoneum have been acquired. These are 

 the colors predominating in the genus Care- 

 proctus which flourishes in regions between 

 100 and 500 fathoms. The vertical distribu- 

 tion of each species is important in consider- 

 ing its coloration. Species such as Cyclo- 

 gaster dennyi and Cyclogaster fucensis, which 

 extend from within 2 or 3 fathoms of the 

 surface down to 123 and 212 fathoms, do not 

 show an appreciable change in coloration. 



Oareproctus is the most interesting genus 

 in the family. It has been derived from the 

 shallow-water genus Cyclogaster and presents 

 the first distinct modification of structure and 

 color caused by the environment of the deep 

 sea. It has given rise, directly or indirectly, 

 to practically all of the other deep-sea genera. 

 The distribution of the species extends from 

 shallow water to great depths, or from 29 to 

 1,823 fathoms. The genus seems to flourish 

 best in the region between 100 and 500 fath- 

 oms. Two thirds of the species are found in 

 this region. 



The coloration of species of Careprocius is 

 very distinct from that typical of the species 

 of Cyclogaster. None of the species are 

 variegated. The nearest approach to this 

 condition is that of Careproctus cyclospilus 

 and Careproctus mirdbilis, two shallow-water 

 species, which have pink blotches over the 

 body. The species are typically translucent, 

 reddish translucent and black. In a number 

 of species the posterior part of the body only 

 is black. It appears that the black pigment 

 encroaches upon the body from the caudal 

 region anteriorly. 



The species of Careproctus can be arranged 

 in three color groups. These groups include 

 the light-colored species, the black species and 



the species intermediate between these two. 

 The light-colored group includes the translu- 

 cent, whitish and reddish species. When 

 placed in alcohol the translucent and reddish 

 appearance is usually lost and the species 

 become an opaque milky white. It is doubtful 

 if any of the species are this color in life. In 

 the black-colored group are included all the 

 black species. In the third group are in- 

 cluded those species which are dusky or have 

 the posterior part of the body, the gill cavity, 

 peritoneum or stomach black. The distribu- 

 tion of these three color groups will be con- 

 sidered separately. 



The light-colored group, consisting of 27 

 of the 38 species of the genus, is represented 

 in depths between 29 and 1,046 fathoms. The 

 majority of these species are found between 

 100 and 500 fathoms. Six species are found 

 in less than 100 fathoms and 4 below 500 fath- 

 oms. The distribution of the light-colored 

 species apparently has no more relation to the 

 273-fathom level than to the 400-fathom level. 

 Eighteen species are found above the 273- 

 fathom level, 13 below it and 4 on both sides, 

 while 22 species are found above the 400- 

 fathom level, 10 below it and 5 on both sides. 



The distribution of the remaining two 

 groups of species does not indicate that the 

 273-fathom level marks the border between 

 two differently colored faunas. The dusky 

 species, of which there are 8, are found be- 

 tween 35 and 887 fathoms, but the majority 

 have been taken between 300 to 500 fathoms. 

 There are 3 species in the black group and 

 these are all from below 405 fathoms. 



The color of the peritoneum is of interest 

 in connection with the color of the body and 

 the distribution. The peritoneum is some- 

 times black when the epidermis is white, but 

 apparently is never white or silvery when the 

 epidermis is black. In preserved specimens 

 it is sometimes difficult to decide whether the 

 peritoneum was originally a dull white or 

 silvery. It appears, however, that the silvery 

 peritoneum is most common with the reddish 

 translucent species. Dr. Hjort reports that 

 the fish fauna above the 273-fathom level is 

 characterized by silvery sides. A sUvery 



