110 A renicolidae 



ill examples from the east coast of the southern United States and 

 from the West Indies and Bermudas ; they are smaller in Californian 

 specimens. 



Neapolitan specimens generally exhibit a considerable number of 

 tail segments : as many as forty may be present (PI. V, Fig. 12). 

 The epidermis of the tail is raised into numerous papillae, but they 

 are all of the same type ; slightly larger ones are present on the 

 larger segmental rings, but there are no thumb-shaped outgrowths 

 such as occur in the American examples described aljove. The 

 specimens from Suez, Barrow Island and Japan agree with those 

 from Naples in lacking special caudal processes. 



The number of nephridia is practically constant in this species. 

 Two interesting departures from the normal number have, however, 

 l)een found : one specimen possessed an additional nephridium on 

 one side, and another had an additional pair, in l)oth cases in the 

 segment following that normally bearing the last nephridia. 



Period of Maturity, Development.— Stimpson and Andrews 

 found the egg-masses of A. cristata about the burrows, on the shores 

 of Carolina, during the latter part of March. The breeding season 

 of this species at Wood's HoU extends from ]\Iay to August, and 

 is at its height in the middle of June. Lo Bianco states that 

 Neapolitan examples are mature from June to August. 



This is the only species of Arcnicola of which the egg-masses are 

 known, and they have been found only on the eastern coast of the 

 United States, at and south of Wood's Holl. They occur in the form 

 of gelatinous ropes, three to four feet long and two to four inches in 

 diameter, each containing several hundred thousand eggs.^ The 

 masses are at first associated with the burrows of the worms, Ijut, as 

 they are swayed about by the tide, they are liable to be washed loose. 

 Accounts of the development and of post-larval stages are given on 

 pp. 74, 75 and 79. 



Distribution. — Arcnicola cristata has been found on the east 

 coast of the United States, from Wood's Holl, ]\Iass. southwards, at 

 a nunil>er of stations, and seems to l)e quite common in some places. 

 Prof. Andrews states that he found it to Ije " abundant " and 

 "excessively numerous" in two localities near Beaufort, N.C. It 

 extends along the western coast of Florichi to Pensacola, which is 

 the most westerly point in the Gulf of Mexico from which the 

 species has been obtained. A. cristata occurs also on several of the 



' 300,000, according to an estimate by Prof. Andrews. 



