GIO PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



depth 25-27 fathoms (10697) ; stations 2405, 2407, 24-30 fathoms (10699) ; 

 station 2408, 21 fathoms (10696) ; station 2414, 26 fathoms (10698). 



The large specimens from station 2407, above mentioned, have long 

 and rather pointed si)ines, and in nearly all eases more or less of the 

 spines were overgrown with clusters of small barnacles, bryozoa, worm 

 tubes and shells.' Fullj- one half the specimens were infested with a 

 species of Stylifer, which was generally found boring into the spines, 

 altbough in one case a single specimen was seen attached to the test^ 

 near the base of a spine, having made there a slight burrow. As many 

 as seven spines were sometimes thns affected in a single specimen, but 

 the usual number was from three to five. The spines attacked were 

 mostly toward the npper surface, but not always so, and were gen- 

 erally those of small to medium size. 



The borings of the Stjilifer jiroduce a curious effect. A small, round 

 hole is first formed in the side of the spine near its base, and the irri- 

 tation apparently induces a continuous deposition of shelly matter, 

 which increases in size until it forms a prominent globular protuberance 

 completely surrounding the spine at the point of irritation. On one 

 side the protuberance is more or less deeply hollowed out, and may 

 contain anywhere from one to eight shells. The spines become stunted 

 in growth, and seldom have more than a small point projecting above 

 the excrescence. The upper part of the protuberance with the tip of 

 the spine may finally break away, leaving the opening to the cavity at 

 the outer end of an abrupt enlargement of the spine. The b«ring gen- 

 erally takes place at the lower end of the spines, frequently just above 

 the base. In a few instances there are quite regular globular termina- 

 tions to short sjnnes without much of a cavity, or with none at all, and 

 these have probably been produced by a deposition of shelly matter 

 over the burrows after the StyUfers had left them. 



The protuberances range in size from a very slight enlargement to 

 twice the diameter of the base of the spine, and are frequently quite 

 grotesque in shai^e and in the appearance of the concavity, the latter 

 being often so large as to leave but a thin shell inclosing it. There are 

 sometimes two or three openings to one protuberance. The outer sur- 

 face generally resembles that of the smaller and smoother spines, but 

 is occasionally covered with a coarse granulation. Its color is a rich 

 brown to brownish black. The spines not infested by StyJifers are all 

 perfectly normal. 



A very small specimen from station 2372 had a single specimen of 

 the same Stylifer upon one of the spines close to the abactiual system. 



Dorocidaris Bartletti A. Agassiz. 



Three fine large specimens were obtained from the following locali- 

 ties : Station 2326, 194 fathoms (10659); station 2331, 114 fathoms 

 (10660) ; station 2335, 204 fathoms (10661). Young specimens were 

 collected at stations 2327, 2337, depth 182, 199 fathoms (10707) ; and 

 characteristic spines at the following stations: 2320, 2322, 2324, 2325, 



