The Philippine Journal of Science, 



D. General Biolog}', Ethnology and Anthropologj-. 



Vol. VI, No. 4, August, 1911. 



ON THE HABITS OF THALASSINA ANOMALA (HERBST). 



By A. S. Peabse.' 

 {From the Zoological Lahoratory, University of the Philippines.) 



Although Thalassina anomala, as Bate- (p. 27) says, is of particular 

 interest because it "supplies a link connecting the macrurous with the 

 anomurous Crustacea," but little has been learned concerning its habits. 

 Again quoting from Bate : 



"We do not know much of the habits of this animal, but many of the group 

 are burrowers in the deposits beneath the seas in which they live, hence it is 

 more than probable, from the matted condition in which I found the fur that 

 covers many parts of the animal, that it inhabits hollow passages in the mud, 

 and that the circulation of the water through the branchial chamber can not be 

 very vigurous * * *." He believed that the structure of the branchife showed 

 that they were capable "of extracting oxygen from water that had been stored 

 for a long period where it lias not been affected by the atmosphere." 



This peculiar crustacean probably occurs throughout the Philippine 

 Islands. Dr. L. E. Griffin informs the writer that it is common in 

 Oriental iSTegros, and it is abundant along the estuaries of Manila Bay. 

 In the latter locality it is called palatah by the Tagalogs. During the 

 months of May, Jime, and July, 1911, the writer made many observations 

 on its habits and ascertained that, though Bate's ^ plates of this animal 

 were very inaccurate, his conjectures concerning its habits were in general 

 correct. Though it may burrow "in the deposits beneath the seas," 

 along Manila Bay the mounds of earth (fig. 1) brought out at the 

 opening of its burrows are found at the edges of estuaries near or above 

 the usual high tide mark. 



Thalassina burrows with the first legs, the dactyls of these appendages 

 being used somewhat like trowels to i^ull the dirt loose. The animal 

 works a load free and then carries the mass before it to the mouth 

 of the burrow. The load is carried in tlie first legs between the dactyl 

 and the propodus, and it may also lie supported below to some extent 

 by the second legs which are held in a horizontal position. The first 

 two pairs of legs form a sort of a basket which is an admirable instrument 

 for sweeping all loose mud before the animal as it moves through its 



' Assistant Professor of Zoology, University of the Philippines. 

 - Bate, C. S. 1888. Report on the Crustacea Maerura dredged by H. M. S. 

 Challenger during the years 1873-1876. Challenger (1888), 24, 27. 



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