Mr. K. I. Pocock on new Geopliilidse. 215 



tive share in the stellate disposition of the organism. Penta- 

 meric repetition is more often exceeded in this than in any 

 other class, and asexual reproduction from a part of the bodj 

 is by no means uncommon. Respiration diffuse. 



The Ophiuroidea are caliculate, actinogonidial, eleuthero- 

 zoic, azygopodous Echinoderms, in which there is no distinct 

 ambulacral groove. The " arms " are sharply marked off 

 from the disk, are very rarely more than five in number, and 

 are sometimes elaborately branched. The digestive system, 

 which is aproctous, and the generative are confined to the area 

 of the disk, as is also the specialized respiratory apparatus, 

 which takes the form of deep clefts. 



The Crinoidea are caliculate, actinogonidial, statozoic 

 Echinodermata, provided with branching articulated arms. 

 In a number of forms the stalked condition is larval only or 

 it is altogether lost ; the power of locomotion is often re- 

 acquired. The aboral nervous system is highly specialized. 

 Gonads developed in the arms. Five or more water-pores 

 establish a communication between the coelom and the 

 exterior. 



It is not necessary for the purpose I have in view to offer 

 definitions of the Cystidea or Blastoidea ; perhaps a palseon- 

 tologist will oblige. 



XXV. — Descriptions of some new Geophilidte in the Collec- 

 tion of the British Museum. ]^y ii. 1. PocOCK. 



[Plate XII.] 



Geophilidse. 

 Henia athenarum^ sp. n, (PL XII. fig. 1.) 



Colour ochraceous j head and maxillipedes darker. 



Body robust, more attenuate anteriorly than posteriorly. 



Head small, wider than long, wider behind than in front, 

 with convex sides ; frontal plate indistinct. 



Antennce of moderate length, filiform, evenly thick through- 

 out, shortly hairy, the segments narrower at their base, the 

 apical segment ovate and longer than the penultimate. 



Maxillary coxce wide, narrowed posteriorly, chitinous 

 lines conspicuous and complete, the anterior border crescentic- 

 ally excavated ; feet short and stout, not attaining, when 



