18G PSAMMOLYCE. 



NOTE XIX. 



ON MALAYAN SPECIES OE THE GENUS 

 PSAMMOLYCE 



BY 



Dr. R. HORST. 



"Worms belonging to the genus PsaiiiDioli/ce, that are 

 characterized by having their elytra and the median part 

 of their back covered with papillae, adapted for the re- 

 tention of small particles of the bottom upon which they 

 are living, hitherto were not observed in the Malay Ar- 

 chipelago. Yet the Siboga-expedition had the good luck to 

 collect a number of them (though often in fragments), 

 that certainly represent three species. However it is no 

 easy task to recognize the characters, offering a trustworthy 

 criterion for the distinction of the species. With regard to 

 the elytra f. i. Willey says: „they are not safe objects for 

 comparison, since they vary from segment to segment" ') ; 

 however Potts rightly stated, that certain features of the 

 elytra as a whole are certainly characteristic for a group 

 of species ^). In Psmnmolijce arenosa ^) and its allies f. i. 

 the elytra are provided with two lobes at their median 

 corner and another lobe at the posterior margin, whereas 

 in an other group of species [Ps. fijiensis **), -occidentaUs ^) 



1) Ceylon Pearl-oyster-fisheries report: Polychaeta, p. 257. 



2) The Percy Sladen Trust expedition: Polychaeta of the Indian Ocean, 

 p. 346. 



3) De St. Joseph, Annelides de St. Jean de Luz : Ann. Sc. nat. Zoölogie 

 (S. 9) t. Ill, 1906, pi. I, fig. 28. 



4) Me Intosh, Challenger Annelida, pi. XXII, figs. 4 and 5. 



Notes from the Leyden Museum, "Vol. XXXV. 



