1890.] NATIKAI. SCIENCES OF FIIILADELril lA. 



ON AKENICOLA CRISTATA AND ITS ALLIES. 



r.Y J. E. IVES. 



During the month of July of last year, my friend ^Ir. Uselma 

 C. Smith collected some specimens of a polychaetous worm, belong- 

 ing to the genus^4;-t''HVc)/a at Anglesea. about ten miles N. E. of Cape 

 May. on the New Jersey Coast. The first specimens seen by him lay 

 iipon tlie beaeh. apparently dead, having perchance left their 

 burrows in the endeavor to reach the water. Upon further examina- 

 tion he discovered a large colony concealed in the sand, along the 

 e»ige of a pool of water formed by the washing over of the sea. Four 

 of these specimens were obtained and subsequently handed over to 

 me in alcohol for identitication. 



They correspond closely to Arenieo/a cristata described by 

 Stimj^sou' in 185G from Charleston, South Carolina, and which, with 

 a doubtful exception.* has not since been reported from the United 

 States. In his recent paper" On Areuicola specimens from the Gulf 

 of Naples," Dr. K. Horst^ has given a detailed account of this species 

 from sj^ecimens obtained in the ^[editerranean. The forms from 

 Anglesea answer both in general and microscopical characters to Dr. 

 llorst's description, the only ditfereuce being that they possess on the 

 ventral surface of the caudal segments small papilhv. which will be 

 referred to again later. Dr. Horst has suggestetl the identity of this 

 species with Arenicola a// ^iV/t/kN'fV described by I^iitken* from the West 

 Indies, and u{>on examination I tind that theXew Jersey sj^cimens 

 correspond as closely as possible to Liitken's description. As alreadv 

 stated, there are on the ventral surface of the caudal segments small 

 papilhv. and these doubtless represent those observed by Dr. 

 Liitken in Arenicola antillensis. These papilhv. however, Dr. Ilorst 

 did not tind in the Mediterranean specimens, but their presence or 

 absence should not, in my opinion, be considered a specific character.. 

 The length of the longest specimen is about 250 mm. 



" Proc. Bost. Soc. Nat. Hist., Vol. 5, p. 114. 



* Webster," Annelida Cliretopoda of New Jersey," oOd Ann. Rep. New \'oik 

 St.ne Mus., 1S79, p. 117. 



5 Notes from the Leyden Museum, Vol. xi, p. -13. 



* Vidensk. Mcddcl. fra Naturk. Forening i Kjobenhavn, 1S64, p. lilO. 



6 



