130 THE VOYAGE OF H.M.S. CHALLENGER. 



VII.— ON THE HABITS OF EECENT CRINOIDS, AND THEIR PARASITES. 



The Crinoids, like the other Echinoderms, are very gregarious in their habits. This 

 is especially the case with those living near the shore and in depths down to 150 fathoms. 

 In Torbay, at Roscoff, in the Bay of Naples, and in many other places large quantities 

 of Antedon rosacea may be readily obtained. Ten thousand individuals of Antedon den- 

 tata are estimated by the officials of the U. S. Fish Commission to have come up at one 

 haul of the dredge off the coast of New England.^ The " Porcupine " dredged Antedon 

 phcdangium in abundance in 50 to 100 fathoms off the Tunis coast ; while the Challenger 

 found Antedon carinata to be very plentiful off the coast of Bahia. Numerous examples 

 of Actinometra jukesi and Actinometra strata were dredged at Cape York, and large 

 quantities of both genera have been obtained in the shallow water round the Phili^ipines 

 by Semper, Meyer, and the Challenger. Station 192, near the Ki Islands (140 fathoms), 

 and Station 214, off the Meangis Islands (500 fathoms), proved to be very prohfic, both 

 in Comatulse (12 and 7 species), and in Pentacrinidae (4 and 6 species) ; and the 

 dredgings of the " Blake " in the Caribbean Sea have yielded similar results. A few 

 stations where Comatute were especially abundant (off St. Vincent, Grenada, and 

 Montserrat, all 120 fathoms or less) also yielded several examples of Pentacjnnus. Prof. 

 Agassiz records that on one occasion no less than one hundred and twenty-four indivi- 

 duals were obtained at a single haul of the bar and tangles.^ 



On the other hand, the score of individuals of Pentacrinus ivyville-tliomsoni dredged 

 by the "Porcupine" in 1870 in 1095 fathoms off the coast of Portugal were unaccom- 

 panied by Comatulas. This is perhaps due to the depth being one at which these Crinoids 

 are comparatively rare ; as two species were obtained, together with fragments of 

 Pentacrinus, within a few miles of this Station, where the depth was 350 fathoms less. 

 Some thirty individuals were taken by the "Talisman" in 1883 at a depth of 1480 metres 

 (800 fathoms); but no information respecting the presence or absence of Comatulceat the 

 same Station has yet been published. 



The Bourgueticrinida3, like the Pentacrinidte, are generally found living in large 

 numbers together. Both Sars and Verrill have obtained numbers of specimens of 

 Rhizocrimis at a single haul of the dredge, and Agassiz records that " on one occasion 

 off Sand Key the dredge must have passed through a forest of them, judging at least 

 from the number of stems and heads of all sizes which it contained."^ Bathycrinus 

 aldrichianus was found by the Challenger to be equally plentiful in the Southern Ocean 

 (Stations 146, 147); and it is evident that in certain localities Crinoids of the more 

 common genera may be obtained in almost any quantity. 



1 Amer. Journ. ^ci. and Arts, vol. xxiii. p. 136. - Bull. Mus. Comp. Zool, 1879, vol. v. p. 296. 



3 Bidl. Mus. Comp. Zool, 1879, No. 1, vol. v. p. 5. 



