DR. TH. MORTENSEN, 



of larvae from the same culture, preserved by Mr. Smith, on the 1st August, 

 being thus a little over one month old. They are represented in Figures 

 10-11. Here the shape of the Luidia larva, so characteristic through 

 the elongated preoral part and the long median processes, is easily 

 recognized. The length of the larva is now 1 mm. Still the development 

 is not sufficiently advanced for showing definitely by which characters 



Fig. 10. Fig. 11. 



FidS. 10-11. — Bipinnaria oi Luidia ciliaris, five weeks old ; 10, front view ; 

 11, side view. 100/1. 



this larva is distinguished from the Bipinnaria of Luidia sarsi. But it 

 can now scarcely be doubted that the larva figured by Garstang, in his 

 paper " On some Bipinnarise from the English Channel,"* is really the 

 larva of L. ciliaris. This species is very common at Plymouth, while 

 L. sarsi is rare ; its breeding season is June to July, and Garstang found 

 the larva in August, I have previously held the opinion that Garstang's 

 larva belonged to L. sarsi ;'f I must now join LudwigJ in the opinion 



* Quart. Jo2irn. Mia: Sci., N.S., 35, 1894. 



t Ecliinoclermcnlarven der Planldon Expediticm 

 Echiiwdermenlarven (p. 11). 



X H Lndwig, " Der Asterideu des Mittelmeeres. 

 Neapcl, 24 Monogr., 1897 (p. 82). 



(p. 40). Nordischcs Plaiikton 

 ' Fauna u. Flora d. Golfes v. 



