1 64 THE CRINOIDEA 



and bearing processes. When stripped of arms and processes, the theca 

 resembles a sherry-decanter with a kick at the bottom. At the junction 

 of cup and tegmen are the 10 pairs of ambulacral openings for food-grooves 

 and associated vessels, which pass beneath the tegmen to a central 

 mouth suspended beneath the neck of the decanter. From this a gut 

 winds dextrally down, around, then up, and out at the mouth of the 

 decanter. The processes borne by the tegmen are vertical partitions 

 rising from the fixed iBr and illBr to varying heights, while smaller 

 partitions are between the IIIBr series. Genera Callicrinus, d'Orb. 

 (1849), Silurian, Europe and N. America (Fig. LXXVIL, see Angelin, 

 1878, W. & Sp., 1897). The cup is built on almost the same plan as 

 that of Clonocrinus, the difference lying in the vertical fission of the 2nd 

 iBr. The partitions do not rise very high between the arm-branches ; 

 on the other hand, large spinous processes are frequently given off from 

 plates of both cup and tegmen, while the upper circlet of the anal 

 tube is often extended in 4 quadrant-shaped horizontal extensions 

 (Cryptodiscus, Hall'; see Weller, 1898). Eucalyptocrinus, Goldfuss (1826 ; 

 syn. Hypanthocrinus, Phillips), Silurian of Europe, N. America, and 

 (?) Victoria, Devonian of Eifel (see Angelin, 1878, and W. & Sp., 1897) ; 

 differs from Callicrinus in the great development of the vertical partitions, 

 which form compartments in which the arms rest right up to their tips, 

 so that the closed crown is almost egg-shaped, especially as it has not the 

 obtrusive ornament of Callicrinus. Angelin has figured laminae of 

 stereom within the theca ; these served to support the subtegminal 

 food-grooves and mouth, and are pierced by the gut ; they are not 

 hydrospires. This family was richer in species than any other of the 

 Silurian ; while the main structure was fixed, the ornament varied 

 greatly. FAMILY 6. DOLATOCRINIDAE. Melocrinoidea with large base, 

 flattened or concave, 3 BB, nearly always fused ; in each half-ray, 1-4 

 IIBr, and sometimes IIIBr and IVBr ; free arms biserial, and may fork ; 

 'Br,3 or more ranges ; illBr usually present, merging with illAnib ; an 

 Additional iBr exceptionally present in post. IR ; tegmen, when known, 

 solid, with large plates ; stem round and large. All Devonian of N. 

 America. Genera Dolatocrinus, Lyon (1857 ; W. & Sp., 1897 ; syn. 

 Cacabocrinus, Hall), has 2 IBr, a stout almost central anal tube, respiratory 

 (?) slits in interbrachial areas at junction of cup with tegmen (Fig. XLV. 1), 

 and plates usually with axial folds. Stereocrinus, Barris (1878, W. & 

 Sp., 1897), has 1 IBr, and BB unfused. Hadrocrinus, Lyon (1869 ; 

 W. & Sp., 1897 ; syn. [?] Coronocrinus, Hall), has 1 IBr and large iBr 

 variable in number and arrangement ; very large, and imperfectly known. 

 The single primibrachs of Stereocrinus and Hadrocrinus probably represent 

 the two IBr of Dolatocrinus fused (cf. Alloprosallocrinus}. 



SUB-ORDER 2. Batocrinoidea. RR in lateral contact except in post. IR. 

 Proximal anal heptagonal. IB^ quadrangular, except in Periechocrinidae. 



FAMILY 1. TANAOCRINIDAE. Batocrinoidea with 6 BB ; the proximal 

 IIBr fixed, but outwardly resemble free brachials ; arms fork still further, 

 brachials wedge-shaped ; iBr and illBr numerous, irregular, occupying 

 depressed areas connected with tegmen, which was probably flexible and 

 composed of small plates ; in post. IR is a vertical ridge of anals ; 



