FASCIOLES OF STARFISHES. ]21 



which the edge of tlie arm is divided by the deep furrows, allowing 

 the passage of the water; at their crossing, the furrows form larger, 

 more prominent openings; the edges of all these rectan- j.^^ jg 



the interambulacral and marginal papilla? into tufts of '^ ^\\ 



such minute spines that the difference between them }> -^~-^-^ 

 and true fascioles is hardly appreciable. In fact, in So- ^ 



laster we have already certain parts of the surface covered by such 

 minute spines that we must consider them as rudi- 

 mentary fascioles and as probably acting as such. 

 a Fig. 17, a cross section of Cribrella, shows a close 



gular spines are crowded with fascioles. The genus Cri- *^^j,^^ Lk' 

 brella is interesting as showing the gradual transition of -T/i^ i^' 



■k' 



-;f^ fipproximation to the cross section of Luidia as far as 

 ' t the tufts of spines are concenied ; these need to be 

 '**^ but slightly more crowded to form a 



most effective sieve. Seen in profile in a section {Fir/. 18), 

 the tufts of spines, the interambulacral papilloe, are seen a4»"i^'^ 

 to be somewhat more crowded into tufts than is the case 

 in such genera as Asteracanthion. A similar arrangement 

 is also found in Solaster (see Fig. 8), where the spines of the interam- 

 bulacral plates, with the exception of those of the so-called jaws, are 

 arranged in closely crowded tufts. 



NOTE. 



The arrangement of the Starfishes into families from the study of their 

 hard parts does not differ materially from the families adopted by Perrier 

 in his Revision of the group.* lie himself has in a general wav made 

 use of the characters furnished by the skeleton to limit the families he 

 has recognized. The modifications we should suggest go so far as to 

 transfer Pycnopodia from the Asteriadte proper, and Crossaster from the 

 Echinasteridae, placing them in close proximity to Brisinga, while Solaster 

 (limited) and Cribrella would be placed with the Asterinida?. 



The disposition of the digestive cavity and its appendages does not 

 appear to furnish systematic characters of great value. The anatomy of 

 the ovaries of the coecal appendages of the digestive cavity proper with 



* Asteriadae, Echinasteridse, Linckiadts, Goniasteridn;, Asteriiiida;, Astroiiectinulae, Ptcrasteridw, 

 Brisinaidae. 



