Comprehensive Description

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Description

"This species is apparently somewhat smaller than H. glacialis, and is distinguished by its more slender form and longer and more slender rostrum, which is prolonged in a slender, unarmed tip, reaching as far forward as the tips of the eyes. The antennal scale is apparently considerably narrower. In the only specimen in which the tip of the telson is perfect, the male from station 2036, it is armed with only four spines, there being only two between the long lateral spines. The most remarkable difference, however, is the first gnathopods, which, as already remarked, bear distinct podobranchiæ. In the larger specimens these branchiæ are conspicuous and composed of several lamellæ each, being nearly as large in proportion to the size of the animal as in Meningodora mollis; but in some of the smaller specimens they are represented by only on or two small lamellæ attached near the base of the epipod, and are very easily overlooked. There are well developed podobranchiæ at the bases of the first gnathopods in all the species of the allied genera known to me, Acanthephyra, Ephyrina, Notostomus, and Meningodora, and I had regarded their absence as one of the best generic characters of Hymenodora, but their occurrence and variability in a species so very closely allied to the typical species of the genus shows that they are not always of generic importance. The two species of Hymenodora still differ, however, from the species of the allied genera above-named in the form of the protognath of the second maxilla and in the number of segments in the endopod of the maxilliped, characters which, for the present at least, may be regarded as of generic value."

 

 

                                                                                                                                                                                                                                                                    
 

 
 

H. glacialis

 
 

H. glacilis

 
 

Catalogue number……………………………………..

 
 

………….

 
 

5456

 
 

7874

 
 

7158

 
 

Station…………………………………………………

 
 

Faröe

 
 

2099

 
 

2182

 
 

2036

 
 

Sex………………………………………………….....

 
 

 
 

 
 

 
 

 
 

Length from tip of rostrum to tip of telson……………

 
 

70

 
 

54+

 
 

55

 
 

43

 
 

Length of carapax, including rostrum…………………

 
 

23.0

 
 

19.0

 
 

18.0

 
 

13.0

 
 

Length of rostrum……………………………………..

 
 

3.0

 
 

2.5

 
 

3.0

 
 

2.3

 
 

Height of carapax……………………………………..

 
 

………….

 
 

10.0

 
 

8.4

 
 

6.8

 
 

Breadth of carapax…………………………………….

 
 

………….

 
 

………….

 
 

7.3

 
 

5.5

 
 

Length of eye-stalk and eye…………………………...

 
 

3.0

 
 

2.3

 
 

2.5

 
 

2.0

 
 

Greatest diameter of eye………………………………

 
 

1.0

 
 

0.8

 
 

0.8

 
 

0.6

 
 

Length of antennal scale………………………………

 
 

9.0

 
 

………….

 
 

6+

 
 

5.7

 
 

Breadth of antennal scale……………………………...

 
 

3.1

 
 

2.4

 
 

2.0

 
 

1.5

 
 

Length of first peræopod……………………………...

 
 

18.0

 
 

………….

 
 

11.5

 
 

10.0

 
 

Length of chela………………………………………..

 
 

4.9

 
 

………….

 
 

3.1

 
 

2.5

 
 

Breadth of chela……………………………………….

 
 

0.7

 
 

………….

 
 

0.7

 
 

0.5

 
 

Length of dactylus…………………………………….

 
 

2.0

 
 

………….

 
 

1.1

 
 

1.0

 
 

Length of second peræopod…………………………..

 
 

………….

 
 

………….

 
 

11.5

 
 

10.0

 
 

Length of chela………………………………………..

 
 

………….

 
 

………….

 
 

3.1

 
 

2.5

 
 

Breadth of chela……………………………………….

 
 

………….

 
 

………….

 
 

0.7

 
 

0.4

 
 

Length of dactylus…………………………………….

 
 

………….

 
 

………….

 
 

1.1

 
 

0.9

 
 

Length of third peræopod……………………………..

 
 

………….

 
 

………….

 
 

3.2

 
 

14.0

 
 

Length of propodus……………………………………

 
 

………….

 
 

………….

 
 

0.5

 
 

3.5

 
 

Length of dactylus…………………………………….

 
 

………….

 
 

………….

 
 

1.2

 
 

1.3

 
 

Length of fourth peræopod……………………………

 
 

………….

 
 

………….

 
 

………….

 
 

16.0

 
 

Length of propodus……………………………………

 
 

………….

 
 

………….

 
 

………….

 
 

4.3

 
 

Length of dactylus…………………………………….

 
 

………….

 
 

………….

 
 

………….

 
 

1.9

 
 

Length of fifth peræopod……….……………………..

 
 

………….

 
 

………….

 
 

21.0

 
 

13.0

 
 

Length of propodus………………………..…………..

 
 

………….

 
 

………….

 
 

6.3

 
 

3.6

 
 

Length of dactylus………………………………….....

 
 

………….

 
 

………….

 
 

2.6

 
 

0.6

 
 

Length of sixth somite of pleon……………………….

 
 

8.3

 
 

7.5

 
 

16.0

 
 

6.5

 
 

Height of sixth somite of pleon……………………….

 
 

4.0

 
 

3.5

 
 

4.6

 
 

2.8

 
 

Length of telson………………………………………

 
 

14.5

 
 

8+

 
 

0.8

 
 

7.8

 
 

Length of inner lamella of uropod…………………….

 
 

10.1

 
 

………….

 
 

7.5

 
 

5.8

 
 

Breadth of inner lamella of uropod……………………

 
 

2.0

 
 

………….

 
 

3.3

 
 

1.1

 
 

Length of outer lamella of uropod……………………

 
 

11.5

 
 

………….

 
 

10.5

 
 

6.5

 
 

Breadth of outer lamella of uropod……………………

 
 

2.7

 
 

………….

 
 

………….

 
 

1.3

 
 

 

(Smith 1886)

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Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

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