CLARK: CRINOIDS. 235 



In B. aldrichianus the stem is represented as having only a single segment wider 

 than high. Judging from B. equatorialis, this segment might easily have been three 

 or four coalesced columnars appearing as a single one, and that following might 

 have been in a similar condition. Even if this were not so, the stem structure of 

 B. equatorialis throws a new light on the specific variation in Bathycrinus, and 

 suggests strongly that the stem of B. aldrichianus as figured is in all essentials 

 correct. At the time the species was dredged by the " Challenger," the only 

 small stalked crinoids on board were five specimens of Rhizocrinus ; as all of the 

 five had the characteristic basals still attached to the stems, confusion with them 

 is out of the question. In the same haul with B. aldrichianus, it is recorded that 

 Hyocrinus stems were secured ; but the stem as figured is certainly not that of a 

 Hyocrinus. Sixteen days later Rhizocrinus was dredged again ; but in this case 

 also the basals were in situ. Four months later Bathycrinus australis and Hyo- 

 crinus were dredged ; but the stem cannot be that of either of these. It was not 

 until the last of February three years later that any more small stalked crinoids 

 were found, too late for their stems to have become incorporated in the figure. 



Type Cat. 22,664, U. S. National Museum, from " Albatross " Station No. 

 4742, 0° 3.4' north latitude, 117° 15.8' west longitude, 2320 fathoms, taken Feb- 

 ruary 15, 1905. 



Bathycrinus caribbeus, sp. nov 



Radials and arms lacking. 



Basals closely united into a smooth ring, slightly wider above than below, 

 longer than wide, the sides perfectly straight. 



Stem 85 mm. long with about one hundred segments, the proximal seven 

 short and discoidal, then rapidly becoming longer, reaching a length of 1.3 mm. 

 with a width of 0.4 mm. in the middle of the stem, the last segment bein"- 

 2.8 mm. long by 1.2 mm. in diameter at its much expanded end. Above the 

 middle of the stem the columnars are cylindrical; distally the articulations be- 

 come more and more prominent and are greatly expanded on the last two 

 segments. 



While it is possible that the elongated basals and small number of short dis- 

 coidal joints in this specimen are indications of immaturity, the completely an- 

 chylosed condition of the basals and the apparently full complement of columnars 

 seem to show that this is not the case ; and that the latter may be characteristic 

 of much larger specimens we have just seen in the case of B. equatorialis. 



Bathycrinus caribbeus forms an interesting addition to the crinoid fauna of 

 the Caribbean Sea, the more so since the depth at which it was found is consid- 

 erably less than the lowest previous record for the genus (B. carpenterii 743 

 fathoms), while the bottom temperature (40° F.) is remarkably high. 



Type Cat. 22,665, U. S. National Museum, from "Albatross" station No. 

 2751, 16° 54' 00" north latitude, 63° 12' 00" west longitude, 687 fathoms; 

 blue Globigerina ooze ; bottom temperature, 40° F. 



The discovery of four species of Bathycrinus since the publication of the 



