1887.] Mrs Griffiths on Specimens q/Tulipa sylvestris. 351 
tulip ( Tulip a sylvestris ) is a descendent from the genus Allium , and 
that by a change in the surroundings and other causes these par- 
ticular plants have retrograded in certain points (namely, the pro- 
duction of an oil identical with oil of onions, and the inflorescence 
similar to the onion family) to the original ancestral type. To con- 
clude, in the words of Darwin, “ As we have no written pedigrees, 
we are forced to trace community of descent by resemblances of any 
kind ” ( Origin of Species). 
5. The Luminous Organs of Nyctiphanes norvegica , Sars. By 
J. T. Cunningham, B.A., and Rupert Yallentin. 
The fact that light was emitted in the dark by a Schizopodous 
shrimp was first noticed by J. Vaughan Thomson, who, in his 
Zoological Researches , published about 1820, describes a species 
which he observed to be luminous under the name Noctiluca. He 
mentions the presence of scattered spots of red pigment in the 
animal, hut was quite unaware that the production of light was 
confined to certain definite organs enveloped by this pigment — was 
indeed unaware of the existence of the organs which form the 
subject of this paper. Later on, when the family of the Euphausiidse 
was defined, various accounts were given of certain complicated 
organs of spherical shape in the animals belonging to the family. 
These organs were generally considered to he organs of vision, and 
were called accessory eyes. The most detailed account of the structure 
of these supposed eyes was given by Claus,* in 1863. The fact that 
the Euphausiidse were luminous, was however known to the naturalists 
on hoard the “Challenger,” and a paragraph is devoted to the subject 
in the Narrative of the Cruise of that ship (vol. i. p. 713). It is 
there stated that the phosphorescent light emitted by the species 
of the Euphausiidse was frequently under observation during the 
voyage. It was found that when one of the animals newly caught 
was taken up by a pair of forceps, a pair of bright phosphorescent 
spots was observed immediately behind the eyes, other two pairs on 
the trunk, and four other spots along the median ventral line of the 
* “Ueber einige Schizopoden und niedere Malakostraken Messina’s,” Zeits. 
f. Wiss. Zool ., Bd. xiii. 
VOL. XIV. 17/11/87 
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