MONOGRAPH OF THE EXISTING CRINOIDS. 293 



Oatoptometra liartlauhi. Colohometra vepretum. 



Heterometra qitindupUcai:n. Colobometra dincolor. 



Amphimelra parilis. Cotylometra gracilicirra. 



Dichrometra ciliata. Oligomcirides iid<;oii<r. 



Cenometra herdmani. Compsometra incommoda. 



Decametra taproianes. Hypalometra defecta. 



Dccametra mylitta. Promachocrinus Icergueloisis. 



Decametra parva. Thaumatometra tenuis, 

 d'. Two bands of spicules, a proximal and a distal, which finally meet and unite. 



Leptonemaster venusftin. Heterometra dengalensis. 



Comatonia cristata. Heterometra compta. 



Eudiocrinus junceus. Heterometra reiinaudii. 



Eudiocrinus pinnatus. Heterometra quinduplicava. 



Eudiocrinus renustulus. Stephanometra echinus. 



Bimerometra hartschi. Oxymetra aranea. 



Craspedometra acuticirra. Lamprometra protectus. 



Heterometra savignii. Oligometra serripinna. 

 Heterometra phiUberti. 

 b\ Tip of the tentacles protected by a calcareous cap. button, ring, or rudimentary plate. 



Neometra alecto. Oephyrometra propinqua. 



Jfeometra acanthaster. Pectinometra carduum. 



Tfeometra conaminis. Pectinometra flavojmrpvrea. 



Neometra gorgonia. Galyptometra lateralis. 



Calometra callista. Paecilometra scalaris. 

 Calometra discoidea. 



A detailed examination of the tentacles was made in 172 individuals. 



Usually all the tentacles in a given specimen agree more or less closely in 

 the frequency and character of their deposits, but this is by no means always the 

 case; it frequently happens that deposits, commonly a few spicules, occasionally 

 considerable aggregations, are found in one or two tentacles of a pinnule but are 

 entirely absent in the remainder, while in the Charitometridse the tentacles in 

 which the tip is protected by a more or less developed plate are mostly confined 

 to the base of the pinnules. 



When adambulacral deposits are absent, deposits in the tentacles are usually 

 also absent, but this is not always so, for in several species in which there is no 

 trace of adambulacral deposits the spiculation of the tentacles is very highly 

 developed. Though in the Calometridise, Thalassometridpe, and Charitometridse 

 the adambulacral deposits are very highly developed, for the most part spicules 

 are few or quite lacking in the tentacles. 



In many cases the spicules in the tentacles are far more conspicuous than 

 the adambulacral deposits, which are often difficult to distinguish from the usually 

 enlarged basal spicules of the tentacles. 



Of the 172 indi\'iduals 87, or approximately half, distributed in all the groups 

 represented, were found to be without deposits in the tentacles; 28, representing 

 the Comasteridse, Zygometridse, Himerometridse, Mariametridse, and Colobo- 

 metridffi, with a few Antedonidse, showed numerous spicules in a conspicuous band 

 along the outer side; 23, representing all groups excepting the Stephanometridse 



