208 Dr. F. A. Bather— A Crinoidfrom the Red Crag. 



■ The Holopodidse, with their ancestors the Eugeniacrinidaj, have a 

 similar massive structure, but had at an earlier period proceeded further 

 in the union of the radials and inclusion of the hasals within them. 



The Apiocrinida?, which are represented in modern seas by Calamo- 

 crinus of the Central Pacific, and in the Cretaceous of Europe by 

 Acrochordocrinus, might possibly receive this fossil ; but the joint-faces 

 of the columnals are marked by radiating striae or by tubercles, and 

 there is no known genus that shows any close resemblance. 



The Bathycriuidte include only the deep-sea form Bathycrinus, 

 a genus which in its possession of a fused basal circlet, followed by 

 discoidal columnals, might seem fitted to receive our fossil. In this 

 genus, however, the radials are very easily separated from the base. 



The Hyocrinidte are also deep-sea forms, namely, Hyocrinus, Gephyro- 

 crinus, and probably Ptilocrinus. jSTo fossil representatives are yet 

 known, but I agree with Professor Jaekel that they are probably 

 descended from the Plicatocrinidte of Jurassic age. It is somewhere 

 in this series that I incline to place our fossil. In the Plicatocrinidse 

 and in Gephyrocrinus and Ptilocrinus the basals are fused. The last 

 two genera have the slender habit characteristic of deep-sea crinoids, 

 but among the Plicatocrinidae Tetracrinus has the massive habit found 

 in crinoids that occupy a more exposed position — the reef-type of 

 Jaekel. The pustular ornament and doliform shape of our specimen 

 are very reminiscent of Tetracrinus. Eemains of the ornament are 

 seen in Gephyrocrinus Grimaldii, Koehler & Bather (1902, figs. 1, 2), 

 as a ring of a dozen small conical tubercles at the proximal margin of 

 the base, projecting beyond the joint-face. Slighter traces are also 

 found in Ptilocrinus antarcticus, Bather (1908). In Gephyrocrinus 

 and Tetracrinus the joint-face of the columnals is plane, with slight 

 radiating grooves at the periphery ; where new columnals are arising, 

 as next the base, the adjacent joint-faces would naturally be more 

 concave. 



On the whole, then, I would suggest that this Red Crag fossil 

 represents the patina (RE and BB) of a shallow-water 

 Crinoid, connecting the Plicatoerinidse with the Hyo- 

 crinidas. It does not quite agree with any of the known genera, 

 and in the absence of further evidence it is hard to say which of them 

 is most closely allied. Among living forms it is perhaps nearest to 

 Gephyrocrinus, but it would be absurd to suppose that it had the 

 peculiar character of the subvective grooves that distinguish that 

 genus, since that character is clearly connected with the deep-sea 

 habitat. On the other hand, it is probably a long way from Tetracrinus 

 in the geological scale, and its superficial resemblance is largely due 

 no doubt to similarity of habitat. Yery likely it represents an 

 undescribed genus ; but I cannot bring myself to base a new generic 

 division and name on so obscure a specimen. Let it be enough for 

 the present to establish a new species, which may provisionally, and as 

 a mere matter of convenience, be referred to Tetracrinus. 



Tetracrinus (?) felix, n.sp. 



Diagnosis. — A Tetracrinus (?) with doliform patina ; RR closely 

 united to each other and to the basal circlet ; proximal border of base 



