VII. Masti(/ocrnnis loreus. 201 



gracilis, antl in a less degree like those of T. caUipi/gus ; they 

 rcsemhlc then) not only in their excessive dichotomy, but in 

 the cliaracter of the brachials and of the covering-plates. In 

 all these respects they differ from the arms of the Cyatho- 

 crinidw, and in all excejjt the regular dichotomy tiiey resemble 

 the arms of Botryocrinus. In the presence of radial sutures 

 and in the arrangement of the columnals the stem resembles 

 that of Ottawacrinus, Thenarocrinus, and Botryocrinus, but 

 approaches nearer the last by reason of its smaller lumen. 



From all these facts, then, it ap[)ears that tiie species must 

 find a place in that line of genera that passes from Dendro- 

 crimis and Ottaioacrinus to Botryocrinus and its allies. 

 When we inquire into which family it should be placed, the 

 obvious answer is — the Dendrocrinida; ; since the possession of 

 regularly dichotomous arms precludes it from finding a place 

 in the Decadocrinidffi. Further, from the non-pinnulate 

 nature of its arms, it must be placed with the Dendrocrinites. 



Comparing it now witii the other Dendrocrinite genera, we 

 see that it differs from Dendrocrinus, llomocrinus, Pariso- 

 crinus, and Thenarocrinus in the total absence of a radianal, 

 in which respect it resembles Merocrinus and Ottawacrinus. 

 In Merocrinus, however, no anal plate of any kind enters 

 into the dorsal cup, so that we are driven back to Ottawa- 

 crinus, 



Ottawacrinus, it will be remembered, has an anal x placed 

 between the radials, but no radianal (see Brit. Foss. Crin. II., 

 * Annals,' ser. 6, vol. v. pi. xiv. fig. 12) ; in the main com- 

 position of its cup, then, it resembles the present species. 

 The stem of Ottawacrinus, too, has very distinct radial sutures. 

 Our new British species cannot, however, be referred to 

 Ottawacrinus, for in that genus the anal x is raised by haL 

 its height above the general level of the radials, while its 

 upper surface supports only two plates of almost equal size. 

 In Ottawacrinus, moreover, the shapes of both basals and 

 radials are curiously irregular on the right side of the cup. 

 The brachials of Ottawacrinus are much flatter, and the 

 articular facet extends over the whole Avidth of tlie radial, so 

 that the arms are closely pressed together below. For the 

 loan of the type specimen of Ottawacrinus canadensis I here 

 tender my hearty thanks to its owner and describer, Mr. W. 

 B. Billings, of Ottawa. 



This new species, then, appears to be sui generis, and it is 

 unfortunately necessary to add to our lists the name Mastigo- 

 crinus. This genus may be regarded as leading in one 

 direction towards the Botryocrinites, and in another towards 

 the Cyathoerinites, 



