64 



Proceedings of the Royal Irish Academy. 



The nature of the spiculatioii is also a character on which great reliance 

 may be placed as a specific deteriniuaut : and, in the case of Scirpcaria, it has 

 proved to be of great value. 



Very good examples of this may be seen in the great contrast between 

 the spicules of Scirpcaria jn-qfimdn and Scirpcaria alba, or between Scirpcaria 

 flagcllwm and Scirpcarifi ramosa, or between Scirpearia furcata and Scirpcaria 

 thomsoni. 



By means, then, of a combination of these characters, it has been possible 

 to arrange the numerous specimens which have been examined into certain 

 fairly definite groups. It will be seen that in the great majority of cases 

 each group is represented by a single species ; but where possible we have 

 suggested affinities. It seems preferable, however, to designate these at 

 present as groups rather than as species, although the latter procedure must 

 also be used for reference. 



It is unnecessary to enter into the details of each group here, as that is 

 much better left over until the various specimens are discussed; but we 

 submit the following classification : — 



SCIEPEAEIA. 

 Division 1. — Main Longitudinal Canals, two in number: — 



(a) profunda-group. 



(6) pectinata-group, 



(c) elongata-group, 



(d) flagellum-group, 



(e) thomsoni-group, 

 (I/) alba-group, 

 (ff) aurantiaca-group, 

 (h) furcata-group, 



(i) andamanensis-group, 

 (j) ramosa-group, 

 (k) ceylonensis-group, 

 {I) maculata-group, . 



Scirpearia profunda emend. 

 Scirpearia hicksoni n. sp. 

 Scirpearia verr^icosa n. sp. 

 Scirpcaria anomala n. sp. 

 Scirpearia pcctinata emend. 

 Scirpearia clongaia emend. 

 Scirpeariu Jlagellmn emend. 

 Scirpearia thomsoni n. sp. 

 Scirpcaria alba emend. 

 Scirpearia aurantiaca emend. 

 Scirpcaria furcata emend. 

 Scirpcaria andamanensis n. sp. 

 Scirpearia ramosa n. sp. 

 Scirpearia ceylonensis n. sp. 

 Scirpearia tnacidata emend. 



Division 2. — Mai7i Longitudinal Canals, FOUK in number : — 

 (a) quadrilineata-group, . Scirpcaria quadrilineata n. s.p. 



