Animal Luminescence 563 



Land and Fresh-ivater Snails 



The only terrestrial mollusc known to produce light is of very 

 recent discovery.-* It is a land snail, Dyakia striata, of the Malay 

 peninsula, discovered and studied by Yata Haneda in 1946. The 

 light organ is situated near the head and emits a flashing, bluish 

 light when the animal is disturbed. Luminous bacteria could not be 

 demonstrated. 



Discovery of a fresh-water snail or limpet in New Zealand is of 

 special interest as the first observed case of a self-luminous fresh- 

 water animal. ^^ The observation was made in 1890 by Henry Suter 

 (1841-1918) , the eminent conchologist of New Zealand. The limpet 

 belongs in the genus Latia and lives in swift-running streams of the 

 North Island. A luminescent mucous free of bacteria is secreted into 

 the water. 



II. Luminous Marine Animals 



Protozoa 



FLAGELLATES 



Discovery of the various microscopic organisms of sea water and 

 the final realization, around 1834, that all phosporescence of the 

 sea comes from ors-anisms, even the " diffuse " lis^ht, has been traced 

 in Chapter XV on " Phosphorescence of the Sea." In particular, the 

 history of knowledge concerning Noctiluca miliaris, the largest of 

 the marine flagellates, has been recorded up to its systematic desig- 

 nation by M. Suriray in 1816, in a manuscript published by J. B. 

 Lamarck in 1836. Within fifteen years the morphology and physi- 



"* An old record of a luminous slug (Limax noctilucus) , discovered by M. d'Orbigny 

 living under stones and dead leaves in the mountains of Teneriffe, is included in Baron 

 de Ferussac's Tableaux systematiques des animaux mollusques, part I: 24, Paris, 1821- 

 1822. No more recent records have appeared. 



^^ The only other fresh-water luminous animals which have been described, owe 

 their light to bacterial infection, such as the " crevette " observed in 1786 by Thulis 

 and Bernard from a stream near Trans in southern France, and the fresh -water 

 shrimp of Lake Suwa, Japan, first seen by a Mr. Ushiyama in 1914 and described by 

 Y. Yasaki in 1927. 



Perhaps aquatic firefly larvae should also be classed as fresh-water luminous ani- 

 mals. Most glowworms are terrestrial, but a species described by Nelson Annandale 

 in 1900 breathed by diffusion of oxygen through the cuticle. Another species described 

 by him in 1906 possessed a tracheal funnel at the posterior extremity which could be 

 extruded like a Snorkel of a submarine, pushed into an air bubble on a plant under 

 water and then withdrawn. K. G. Blair in 1927 described a third type of aquatic 

 lampyrid larva, which breathed by tracheal gills. 



