LEPTOSTRACA, SCHIZOPODA AND STOMATOPODA. 179 



Belonging TO the oenus Lysiosquilla, Dana. 

 Lysioerichthus duvaucellii ((Juekin). 



Locality : East of Gallehogalle Bank, 16 to 30 fathoms, fine sand. One specimen, 

 22 nnllims. long, excluding rostrum. 



The single example which I refer to this distinct and rather remarkable species 

 agrees in all particulars save two with Claus' figures (Claus, 1871, fig. 16). The 

 first point of difference lies in the complete absence from the present specimen of 

 a dorsal spine. In Claus' figure the latter is represented by a slight acumination 

 only. 



The Ceylon specimen has two very small spinules between the submedian and 

 intermediate spines of the telson and a very small one at the base of the lateral 

 spines. These spinules are not represented in Claus' figures, but are so small as 

 to be easily overlooked. The raptorial claw shows indications of seven teeth below 

 the skin, and the outer uropod is armed with five not fully developed spines. 



From a comparison of the Ceylon specimen with the figures of L. duvaucellii given 

 by Claus (1871), Brooks (1886), and Jurich (1904), it seems at least doubtful that 

 all three writers were dealing with the same species. 



It is unfortunate for an absolute settlement of this point that Claus omitted to 

 mention the length of his specimen. The Ceylon example, which seems almost 

 certainly to belong to the same species as Claus', measures 22 millims. without the 

 rostrum, but is considerably more developed than Brooks' largest specimen (which 

 is stated to be over an inch, i.e., 25 millims. in length), in having more segments of the 

 abdomen exposed below the carapace, in the limbs of these segments being much more 

 advanced in development as shown by the appearance of gills and in having more spines 

 on the outer uropod, and differs in the absence of the dorsal spine of the carapace. 

 Jurich's largest specimen, which measures 20*5 millims. without the rostrum, agrees 

 with Brooks' figures in all essential particulars, and the differences between them, 

 namely, the less developed abdomen and the absence of indications of teeth beneath 

 the skin of the raptorial claw in Jurich's specimen, are only those of age. From these 

 considerations it seems improbable that Brooks' and Jurich's specimens belong to 

 the same species as Claus', though certainly very nearly allied. Brooks mentions 

 that some of his larva? were without the dorsal spine on the carapace, but, if this latter 

 gradually becomes obsolete as larval development proceeds, we should naturally expect 

 that it would be his largest larvae which would be without the spine. This is not so, as 

 is apparent from the text. It is more probable that he had two species of larva? under 

 consideration. As already noted, a definite conclusion on this point is precluded 

 by a want of knowledge of the size of Claus' larva, but the possibility of two closely 

 allied species of larvae having been confounded under the one specific denomination, 

 L. duvaucellii, seems worthy of notice. 



Distribution : Bay of Bengal (Guerin) ; Indian Ocean (Claus) ; West Pacific 

 ("Challenger"); Indian North Equatorial Current (Jurich). 



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